Functionalized Carbon Nanotubes Encapsulated Alginate Beads for the Removal of Mercury Ions: Design, Synthesis, Density Functional Theory Calculation, and Demonstration in a Batch and Fixed-Bed Process.

Various nanomaterials have been envisaged mainly through batch studies for environmental remediation application. The real utilization of these new generation adsorbents in large scale pose a difficulty due to its low density and small size which makes it difficult for isolation after application. In this context, nanoadsorbents polymer composite beads can be seen as a way out. Here, functionalized CNTs (carbon nanotubes) have been fabricated into micro beads with sodium alginate. The alginate-functionalized CNT (Alg-f-CNT) beads were then comprehensively evaluated for batch and fixed-bed column separation of divalent mercury ions from an aqueous medium. The effects of process parameters such as pH, contact time, feed Hg2+ concentration, and temperature were studied. Simulation of the experimental data suggested that adsorption is an endothermic spontaneous process which follows the pseudo-second-order kinetic and Langmuir isotherm model. The desorption of the Hg2+ ion from used adsorbent was possible with 1 M HNO3. The breakthrough curves at different process parameters were investigated during fixed-bed column separation and found to be in good agreement with Thomas model. The regeneration and reusability of the adsorbent were tested up to five cycles without a significant decrease in the removal performance. Density functional theory studies revealed stronger interaction of Alg-f-CNT with Hg compared to free alginic acid and established the role of carboxyl and oxo groups present in the adsorbent in the coordination of the Hg2+ ions. The experimental results demonstrate that functionalized CNT-encapsulated alginate beads are a promising alternate material, which can be used to remove mercury in the fixed-bed column mode of the operation.

Industrial heat island mitigation in Angul-Talcher region of India: Evaluation using modified WRF-Single Urban Canopy Model.

Linkages of urban and industrial cooling with sustainable development goals and climate change perspectives are well acknowledged, mainly for developing economies in tropical climates. Angul-Talcher region is one of the oldest industrial clusters of India, and the region experiences higher atmospheric heat island intensities with magnitudes of 7 to 9 °C attributed to the Industrial Heat Island (IHI) effect. In the present study, various measures for mitigating heat island effect in the region and assessed their impact using an Improved Weather Research and Forecasting model coupled with the Single-Layer Urban Canopy Model. The improved framework includes the release of industrial emissions at stack height and sector-wise diurnal profiles of anthropogenic heat (AH) released from vehicles, residential, and industry/power. The mitigation measures comprised strategies like alteration in building materials and conversion of landuse-landcover (LULC) of selected grid cells in the model domain to more vegetation or water bodies. It was noted that the cool roofs and walls together reduced IHIs by 0.5 °C, while green roofs and cool pavements achieved a reduction of 0.3 °C and 0.1 °C, respectively. The introduction of water bodies showed maximum reduction in IHIs by 3 to 5 °C during daytime and 1 to 2 °C over mining and industrial stations. During night-time, conversion to mixed forests was more effective (ΔT ≈ 1 °C) than conversion to water bodies. A combination of cool roofs with the introduction of water bodies in the mining areas and mixed forest patches in industry stations was found to be the most effective mitigation strategy for mitigating the industrial heat island effect over the Angul-Talcher region. These mitigation scenarios can/should serve as a theoretical reference for implementing actual mitigation measures, which would require consideration of economic, social, and policy aspects apart from scientific ones for practical application.

Withholding methotrexate after vaccination with ChAdOx1 nCov19 in patients with rheumatoid or psoriatic arthritis in India (MIVAC I and II): results of two, parallel, assessor-masked, randomised controlled trials.

Background: There is a necessity for an optimal COVID-19 vaccination strategy for vulnerable population groups, including people with autoimmune inflammatory arthritis on immunosuppressants such as methotrexate, which inhibit vaccine-induced immunity against SARS-CoV-2. Thus, we aimed to assess the effects of withholding methotrexate for 2 weeks after each dose of ChAdOx1 nCov-19 (Oxford-AstraZeneca) vaccine (MIVAC I) or only after the second dose of vaccine (MIVAC II) compared with continuation of methotrexate, in terms of post-vaccination antibody titres and disease flare rates. Methods: MIVAC I and II were two parallel, independent, assessor-masked, randomised trials. The trials were done at a single centre (Dr Shenoy's Centre for Arthritis and Rheumatism Excellence; Kochi, India) in people with either rheumatoid arthritis or psoriatic arthritis with stable disease activity, who had been on a fixed dose of methotrexate for the preceding 6 weeks. Those with previous COVID-19 or who were positive for anti-SARS-CoV-2 nucleocapsid antibodies were excluded from the trials. People on high-dose corticosteroids and rituximab were also excluded, whereas other disease-modifying antirheumatic drugs were allowed. In MIVAC I, participants were randomly assigned (1:1) to stop methotrexate treatment for 2 weeks after each vaccine dose or to continue methotrexate treatment. In MIVAC II, participants who had continued methotrexate during the first dose of vaccine were randomly assigned (1:1) to withhold methotrexate for 2 weeks after the second dose of vaccine or to continue to take methotrexate. The treating physician was masked to the group assignments. The primary outcome for both MIVAC I and MIVAC II was the titre (absolute value) of anti-receptor binding domain (RBD) antibody measured 4 weeks after the second dose of vaccine. All analyses were done per protocol. The trials were registered with the Clinical Trials Registry- India, number CTRI/2021/07/034639 (MIVAC I) and CTRI/2021/07/035307 (MIVAC II). Findings: Between July 6 and Dec 15, 2021, participants were recruited to the trials. In MIVAC I, 250 participants were randomly assigned and 158 completed the study as per the protocol (80 in the methotrexate hold group and 78 in the control group; 148 [94%] were women and 10 [6%] were men). The median post-vaccination antibody titres in the methotrexate hold group were significantly higher compared with the control group (2484·0 IU/mL, IQR 1050·0-4388·8 vs 1147·5 IU/mL, 433·5-2360·3; p=0·0014). In MIVAC II, 178 participants were randomly assigned and 157 completed the study per protocol (76 in the methotrexate hold group and 81 in the control group; 135 [86%] were women and 22 [14%] were men). The methotrexate hold group had higher post-vaccination antibody titres compared with the control group (2553·5 IU/ml, IQR 1792·5-4823·8 vs 990·5, 356·1-2252·5; p<0·0001). There were no reports of any serious adverse events during the trial period. Interpretation: Withholding methotrexate after both ChAdOx1 nCov-19 vaccine doses and after only the second dose led to higher anti-RBD antibody titres compared with continuation of methotrexate. However, withholding methotrexate only after the second vaccine dose resulted in a similar humoral response to holding methotrexate after both vaccine doses, without an increased risk of arthritis flares. Hence, interruption of methotrexate during the second dose of ChAdOx1 nCov-19 vaccine appears to be a safe and effective strategy to improve the antibody response in patients with rheumatoid or psoriatic arthritis. Funding: Indian Rheumatology Association.

Evaluation of quaternization effect on chitosan-HAP composite for bone tissue engineering application.

This study attempts to improve the aqueous solubility of chitosan and utilizes it in the fabrication of composites with hydroxyapatite (HAP). The composites were evaluated as a curcumin delivery vehicle for bone regeneration. The chitosan was modified by quaternization, with a quaternization degree of 5 % for low quaternized chitosan (LQC) and 11 % for high quaternized chitosan (HQC). The modified chitosan, at alkaline pH 11, facilitated in situ HAP growth and formed LQC-HAP and HQC-HAP composites. The quaternization weakens intermolecular hydrogen bonds, facilitates interaction with the apatite precursor ions and promotes the growth of HAP. The modification significantly improved drug encapsulation (2.6 fold) but at the cost of a slight decrease in mechanical strength and increase in drug release. The in vitro studies with human osteoblast-like MG-63 cells established that the curcumin-loaded composites, LQC-HAP-C and HQC-HAP-C are biocompatible, encourage proliferation and promote a 2-fold increase in calcium mineralization over drug-free composites. The study exemplifies the reciprocity between quaternization degree and drug load/release properties and also illustrates that the magnitude of the latter reflects bioactivity. Thus, the quaternized chitosan-based HAP composite with tailorable bio-physicochemical properties becomes an interesting drug delivery system in bone regeneration.

Herpes zoster following vaccination with ChAdOx1 nCoV-19 Coronavirus vaccine (recombinant).

Ever since the emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, science has unraveled much knowledge on SARS-CoV-2 which has led to extraordinary and unprecedented progress in developing COVID-19 vaccines. Several adverse cutaneous reactions, ranging from more common local injection site reaction, neutrophilic and pustular drug reactions to flare-up of preexisting dermatoses, have been reported with currently available vaccines. We report a case series of 7 patients who developed herpes zoster (HZ) following the first dose of ChAdOx1 nCoV-19 coronavirus vaccine (recombinant). HZ following vaccination is a rare entity. The occurrence of HZ in the patients presented in this series within the time window 1-21 days after vaccination defined for increased risk and postulated dysregulation of T-cell-mediated immunity, suggests that the ChAdOx1 nCoV-19 coronavirus vaccine (recombinant) could probably be a trigger for reactivation of varicella zoster virus to cause HZ in them.

Lactational polychlorinated biphenyls exposure induces epigenetic alterations in the Leydig cells of progeny rats.

The present study was designed to establish the epigenetic mechanisms by which lactational exposure to PCBs affects the Leydig cell function in progeny rats. The lactating dams were oral gavaged with different doses of PCBs [1, 2 and 5 mg/kg or corn oil ] and Leydig cells were isolated from the testes of progeny rats at postnatal day (PND) 60. We assessed the expression of transcription factors regulating steroidogenic machinery and the promoter methylation of LHR and AR in the Leydig cells. Our results confirmed hypermethylation of SF-1, Sp1/3, LHR and AR genes. There was a significant reduction in the gene expression of SF-1 and Sp1. The mRNA expression of Sp3 was decreased. Interestingly, there was an increased gene expression levels of DNA methyltransferases (Dnmts) (Dnmt1, Dnmt3a/b and Dnmt3l) and unaltered histone deacetylase-1 (Hdac-1). Furthermore, increased percentage of 5-methylcytosine was observed in PCBs exposed Leydig cells. Taken together, our findings suggest that promoter hypermethylation of SF-1, Sp1/3, LHR and AR could have led to transcriptional repression of these genes in Leydig cells. In conclusion, our study demonstrates that lactational exposure to PCBs caused epigenetic changes in the Leydig cells which could have impaired the Leydig cell function in progeny (PND60) rats.

Effect of Foot Reflexology on Reduction of Labour Pain Among Primigravida Mothers.

BACKGROUND: Reflexology may help induce labour and reduce pain during childbirth. Fear of pain associated with childbirth leads to increase in the irregular use of cesarean method. PURPOSE: This study was performed to evaluate the effect of reflexology on relieving labour pain and assess the recipient's opinion regarding foot reflexology. SETTING: The study taken place in the labour room, Amrita Institute of Medical Sciences, Kerala, South India. PARTICIPANTS: 50 primigravida patients experiencing labour. RESEARCH DESIGN: A quasi-experimental study design was used. Subjects were selected by convenience sampling technique with the first 25 patients allocated to the experimental group and the successive 25 primigravida mothers to a time-control group, to avoid data contamination. INTERVENTION: Intervention consisted of foot reflexology applied by a trained therapist to five pressure points of both feet that correspond to the uterus. Total intervention time lasted 20 minutes. Control group rested quietly for 20 minutes to serve as a time control. MAIN OUTCOME MEASURES: Pain associated with labour was recorded on a visual analogue scale immediately prior to intervention, and at 20- and 40-minutes postintervention. Patient satisfaction with reflexology treatment was recorded. RESULTS: Mean baseline pain score in foot reflexology group was significantly reduced across the study timeframe relative to control group (p < .001). Post hoc tests confirmed a reduction in labour pain at both the 20-min (p < .001, 95%CI 0.764-1.796) and 40-min (p < .001, 95%CI 0.643-1.677) time points. Eighty-one per cent of patients would recommend reflexology during labour. CONCLUSION: The findings showed that foot reflexology was effective in relief of labour pain, with a high degree of patient satisfaction in primigravida mothers.

Quercetin attenuates metastatic ability of human metastatic ovarian cancer cells via modulating multiple signaling molecules involved in cell survival, proliferation, migration and adhesion.

Ovarian cancer is the most deadly gynaecology related cancer due to its high metastasizing ability. Quercetin is the most abundant flavonoids received increased interest due to its anti-cancer properties. Although the anticancer property of quercetin is very well known, its anti-metastatic effect on metastatic ovarian cancer cells and their underlying molecular mechanism remains to be elucidated. Quercetin treatment at 50 µM and 75 µM concentration inhibit human metastatic ovarian cancer PA-1 cell survival and proliferation via inactivating PI3k/Akt, Ras/Raf pathways and EGFR expression. It also alters the expression of N-cadherin in PA-1 cells. Quercetin also decreases the secretion of gelatinase enzyme, proteolytic activity of MMP-2/-9, and both MMPs gene expression in metastatic ovarian cancer PA-1 cells. In addition to this quercetin inhibits the migration of PA-1 cells. Treatment of quercetin with PA-1 cells also downregulates the tight junctional molecules such as Claudin-4 and Claudin-11 while upregulates the expression of occludin. It is further validated by cell adhesion assay in which quercetin reduces the adhesion of PA-1 ovarian cancer cells. Results suggest that quercetin inhibits cell survival, proliferation, migration, and adhesion which plays crucial role in ovarian cancer metastasis. Hence, it could be a valuable therapeutic drug for the treatment and prevention of metastatic ovarian cancer.

Dysphagia and disability in minor strokes - An institutional study.

BACKGROUND: Minor strokes, defined as NIHSS ≤5 are considered non-disabling, associated with a favourable outcome. AIM: Our aim was to study prevalence and predictors of dysphagia in patients with minor stroke and its impact on functional outcome. METHODS: Single centre retrospective study of all minor strokes admitted to Comprehensive Stroke care centre with 1 year completed follow-up were recruited. Clinical and imaging details and follow-up data were extracted from medical records. RESULTS: We had 147 patients with minor stroke, 72.1% men with median age 61 years. 71% presented within 24 h of symptom onset. Most common etiology was lacunar .Median NIHSS at admission was 3(IQR 2). 85 patients had anterior circulation strokes and 34 had chronic infarcts in imaging.19 had significant dysphagia and 10 were discharged with nasogastric feeding tube. Admission NIHSS and white mater changes in imaging were predictive of post stroke dysphagia. Excellent recovery of dysphagia was found within 1 month post stroke in all, except one who required percutaneous gastrostomy. At 3 months 76% had excellent outcome. Presence of dysphagia and diabetes were found to be predictive of short term outcome, independent of admission stroke severity. At 12 months, post stroke dysphagia, female gender and white mater changes in imaging were predictive of unfavourable outcome. CONCLUSIONS: Minor strokes are disabling in a small fraction of patients. Over 10% of them can have significant post stroke dysphagia necessitating nasogastric feeding short term. This patient subgroup tend to have less favourable outcome on short and long term follow-up.

Asymptomatic Hearing Impairment Frequently Occurs in Early-Onset Parkinson's Disease.

OBJECTIVE: Recent reports of hearing impairment in Parkinson's disease (PD) have suggested that auditory dysfunction could be a non-motor manifestation of PD. These reports were based on observations of elderly patients for whom presbycusis may, to some extent, have contributed to hearing dysfunction. Therefore, we aimed to explore the auditory functions in younger patients with PD. METHODS: We conducted a case-control study in a relatively younger (< 55 years of age at study time) population of PD patients and healthy volunteers to test whether auditory dysfunction is a significant non-motor dysfunction in PD. Pure tone audiometry (PTA) and brainstem evoked response audiometry (BERA) were performed in all participants. RESULTS: None of the patients or controls reported hearing deficits. Fifty-one patients with PD and 50 healthy volunteers who were age- and gender-matched to the patients participated. PTA-detected hearing impairment was found in 64.7% of patients and 28% of controls (p < 0.001) for both low-mid and/or high frequencies. Hearing impairment was more frequent in the younger subgroups of patients than age-matched controls, while the frequency of hearing impairment was similar in older groups of subjects. BERA was not different between patients and controls. CONCLUSION: Asymptomatic auditory dysfunction is a common non-motor manifestation of early-onset PD and more frequent in younger patients, indicating that it may be independent of aging. The mechanism underlying this dysfunction appears to be peripheral, although a central dysfunction cannot be ruled out based on the findings of this study.

Anti-hyperglycemic Properties of a Purified Proteinaceous Protease Inhibitor from Macrotyloma Uniflorum Seeds.

INTRODUCTION: Fabaceae are a rich source of protease inhibitors. METHODS: A proteinaceous protease inhibitor of 25 KDa designated as Macrotyloma uniflorum protease inhibitor (MUPI) was isolated from seeds of Macrotyloma uniflorum and purified to homogeneity by ammonium sulphate precipitation, DEAE Sepharose column and CNBr activated Sepharose 4B Trypsin affinity chromatography. The purity was checked by reverse phase HPLC. Long-term type 2 diabetes can lead to various biological complications, such as hypertension and heart-related diseases. The glucose uptake studies were carried out with the purified MUPI and it reveals its potential to be explored as a potent anti-hyperglycemic agent. MUPI was rendered safer on HepG2 cells after MTT cytotoxicity assay. RESULTS: The results of glucose uptake studies suggest MUPI to be equally efficient to that of the positive control drug Metformin against diabetes mellitus. CONCLUSION: The significance of plant-based inhibitors for modulating carbohydrate breakdown and control of glycemic index is explored to reduce the risk factors and side effects of the available drugs.

Antifungal and Antimicrobial Properties of a Purified Protease Inhibitor from Macrotyloma Uniflorum Seeds.

BACKGROUND: Plant protease Inhibitors (PIs) play key roles in regulation of many biological activities and being less toxic, more potent and specific in comparision to chemical inhibitors. METHODS: A new proteinaceous trypsin inhibitor was isolated and purified from Macrotyloma uniflorum seeds with a molecular mass of 25 KDa was purified to homogeneity via three sequential purification steps i.e., ammonium sulphate precipitation to CNBr activativated Sepharose 4B coupled trypsin affinity chromatography. Purified protease inhibitor (PI) showed optical specific activities of 665 µmols of tyrosine released/ml/min. RESULTS: Overall, there was a remarkable increase in the fold of purification. MUTI is stable to denaturation by heat (upto 80°C), pH (4-10).The inhibitory activity increased to two fold in the presence of mercuric chloride and got reduced by half in the presence of ferric chloride. SDS, Dithiothreitol, ß-mercaptoethanol, Hydrogen peroxide, Triton X 100 enhanced its inhibitory activity whereas activity was reduced in the presence of DMSO. Chemical modification of the inhibitor by DEPC decreased its activity but the activity was increased considerably when modified with NE and PMSF. Presence of protease inhibitor activity was confirmed by reverse zymography and Dot- blot. Also MUPI has antifungal and antimicrobial properties. MUPI inhibited Phytophthora capsici by 16.6% and Rhizoctonia solani by 27.7%. CONCLUSION: Antibacterial activity was shown against Staphylococcus aureus and Pseudomonas aeruginosa. MUPI retained 90% inhibition upon storage at 4°C for over a period of six months. Thus PI can be effectively exploited to increase the shelf life of seafood.

Screening, Purification and Characterization of Protease Inhibitor from Capsicum frutescens.

Plants are rich in protease inhibitors (PI) and trypsin inhibitors are the most common. Therefore, it is of interest to screen PI from plant sources. We report the screening, purification and characterization of PI from Capsicum frutescenes. The partially purified PI showed bands corresponding to 21 KDa and was further confirmed using reverse zymography. The enzyme was stable at temperatures below 60°C and a wide range of pH with 65 folds purification. The effect of magnesium ions oxidizing and reducing agents on PI is reported. The large-scale isolation and purification of PI from Capsicum frutescenes is of commercial interest.

Evaluation of prevalence and risk factors of gestational diabetes in a tertiary care hospital in Kerala.

AIMS: The prospective study was conducted with the aim to evaluate the prevalence and risk factors of gestational diabetes mellitus in a tertiary care referral hospital in Kerala. MATERIALS AND METHODS: A prospective observational study was conducted with the aim to study the prevalence, risk factors, complications, treatment pattern and cost analysis of GDM. The study was carried out in the Obstetrics & Gynecology dDepartment of Al Shifa hHospital located in northern Kerala. RESULTS: Over an eight-month period, 201 patients who met the inclusion criteria were enrolled for study from which prevalence of GDM was estimated at 15.9%. The study revealed higher prevalence of risk factors and complications such as age >25 years, BMI >26kg/m(2), family history of DM, past history GDM, history of big baby, gestational hypertension, vaginal candidiasis, premature rupture of membranes and hyperbilirubinemia in GDM group as compared to non-GDM group. The study also demonstrated that modern life-style was a major influencing factor for development of diabetes in the study population. CONCLUSION: The study reveals the necessity of proper screening diagnosis and management of GDM in pregnant women by the clinicians so as to prevent the future burden of type 2 diabetes.

Impact of urbanization and land-use/land-cover change on diurnal temperature range: a case study of tropical urban airshed of India using remote sensing data.

Diurnal temperature range (DTR) is an important climate change index. Its knowledge is important to a range of issues and themes in earth sciences central to urban climatology and human-environment interactions. The present study investigates the effect of urbanization on the land surface temperature (LST) based DTR. This study presents spatial and temporal variations of satellite based estimates of annually averaged DTR over megacity Delhi, the capital of India, which are shown for a period of 11 years during 2001-2011 and analyzes this with regard to its land-use/land-cover (LU/LC) changes and population growth. Delhi which witnessed massive urbanization in terms of population growth (decadal growth rate of Delhi during 2001-2011 was 20.96%) and major transformations in the LU/LC (built-up area crossed more than 53%) are experiencing severity in its micro and macroclimate. There was a consistent increase in the areas experiencing DTR below 11°C which typically resembled the 'urban class' viz. from 26.4% in the year 2001 to 65.3% in the year 2011 and subsequently the DTR of entire Delhi which was 12.48°C in the year 2001 gradually reduced to 10.34°C in the year 2011, exhibiting a significant decreasing trend. Rapidly urbanizing areas like Rohini, Dwarka, Vasant Kunj, Kaushambi, Khanjhawala Village, IIT, Safdarjung Airport, etc. registered a significant decreasing trend in the DTR. In the background of the converging DTR, which was primarily due to the increase in the minimum temperatures, a grim situation in terms of potentially net increase in the heat-related mortality rate especially for the young children below 15years of age is envisaged for Delhi. Considering the earlier findings that the level of risk of death remained the highest and longest for Delhi, in comparison to megacities like Sao Paulo and London, the study calls for strong and urgent heat island mitigation measures.

Influence of aerosol spectrum and air pollutants on fog formation in urban environment of megacity Delhi, India.

Urban areas are facing increasing fog frequencies that may result due to increased air pollution emanating from variety of sources. The increased pollution levels may lead to the atmospheric reactions resulting into the formation of secondary pollutants that may also lead to increased aerosol number concentrations (ANC) in the atmosphere. This could cause enhanced water aerosols in the presence of favourable meteorological conditions and high relative humidity. This study deals with the atmospheric pollution and visibility during winter season of megacity Delhi in order to assess the relationship between the two specifically during fog episodes. Thus, this study analyses the levels of air pollutants, aerosol spectrum and meteorological conditions during one week each in the winter season of the years 2004 and 2006 in order to have an improved understanding of their role in fog formation in mega-city Delhi. More than 300 h of measurements which included episodes of dense, thick and moderate fogs of about 25 h, were studied. The measurements cover most of the accumulation mode and greater size spectrum of aerosols. Thus, the analysis is performed for the entire period, specifically, before the fog sets up, during and afterwards. In general, the relatively small variations in number concentration show larger variations in visibility prior and post dense fog formation than during dense fog episodes. Preliminary analysis of monthly averaged RSPM (Respirable Suspended particulate Matter or PM(10)) concentration values for four winter months for a period of 6 years (1996-2001) and visibility did not show a good correlation with total occurrences of fog. However, daily averaged RSPM concentration showed a good correlation with the occurrences of thick fog. Diurnal variation of Sulfur-dioxide and Nitrogen dioxide were found to have inverse relationship with visibility during fog which may be due to formation of secondary pollutants such as sulfate and to a lesser extent nitrates. Amongst, the daily averaged concentrations of all the criteria pollutants, RSPM was found to be best correlated with the fog in comparison to other pollutants.

An analysis of the annual and seasonal trends of air quality index of Delhi.

The Air Quality Index (AQI) is an index for reporting daily air quality. A study on the annual and seasonal variations of Air Quality Index over a period of 9 years (1996-2004) based on daily averaged concentration data of criteria air pollutants has been conducted for Delhi. An attempt has been made to quantify the changes in the AQI on annual and seasonal (winter, summer, monsoon and post monsoon) basis for 9 years. Measurements for the seven monitoring sites (Nizamuddin, Ashok Vihar, Shahzada Baug, Shahadara, Janakpuri, Sirifort and ITO) in Delhi were analysed and trends were also compared amongst these sites. Maximum Operator Function method was used to compute the Air Quality Index of the above areas and percentage variations in different severity class is discussed which provides in depth analysis of the trends. The best air quality was depicted by Shahzada Baug followed by Shahdara, both of these were classified as industrial areas indicating that policy measures relating to the industries in the city during past years have helped in improving the air quality. The air quality in other areas have improved slightly in the span of nine years but still remains critical indicating continued rigorous efforts in this direction. Increased traffic density seems to have resulted into the worst air quality at ITO in the city amongst all the monitoring stations. There is a shift for the worst AQI in the city from winter to summer season in a time span of these nine years. Change of season for worst AQI from Winter to Summer may also be likely due to increased photochemical reactions playing major role with change in the nature of emissions imposed due to different control measures such as CNG implementation, significant shift to LPG in domestic sector etc. calling for a detailed study, those which started after the year 2000. After the year 2000, there is a significant increase in the Nitrogen-dioxide (NO(2)) concentration at all stations. ITO which has shown continuous exponential increase in pollution levels has first time showed a declining AQI trend in the year 2004 and one of the contributing factors could have been the Delhi metro (initiated in 2002) passing through congested neighbouring areas causing traffic decongestion here. In general, the areas which are farthest from metro route viz., Siri-fort, Nizamuddin, Janakpuri etc. did not record declining AQI in 2003 onwards as happened with stations closer to Metro route such as Ashok Vihar and ITO. An attempt has been made to quantify the reasons that lead to the changes in the values of the AQI.