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Since the air pollution and noise generated from fireworks are related to air quality and human health, the regulatory bodies had implemented the eco-friendly "Green Crackers" in megacity Delhi, India, to celebrate Diwali 2019 with the permission of a specific time slot (8:00 p.m. to 10:00 p.m.). The present study was conducted on a residential educational institute campus to evaluate the particle number size distribution (PNSD) of green cracker emissions. During the Diwali event period, the high peak of particle number concentration (PNC) reached 1.7 × 10

According to a global survey of 1600 cities by WHO in 2015, Delhi was found to be the most polluted city in the world, highlighting immediate need to bring in appropriate and effective measures to ensure a healthy air quality throughout the city. In a bid to do so, the odd-even driving scheme was implemented a few years ago in Delhi city on a trial basis requiring the vehicles bearing odd and even registration numbers to run on alternative days with effect from 1st January 2016. Applied for the very first time in India and lasting on a pilot basis for 15 days and also referred to as Phase 1 of implementation, the scheme ended on 15th January 2016 with primary goal of assessing the extent to which such a scheme could serve as an effective measure to bring down and control the excessively high ambient air pollution levels. Other associated benefits, which the study considered, were decongestion of city roads, and promoting use of public transport system and carpooling, besides other alternative modes of transport. The paper presents a comparative analysis of particulate matter concentrations recorded before and during the implementation of odd-even scheme of Phase 1 for three key traffic corridors of the city. The study reports an average reduction of PM2.5 of 5.73% and that of PM1.0 of 4.70% in the ambient air across all the corridors during the days of implementation of scheme, which depicts a small but positive impact of the measure adopted towards abatement of urban air pollution in the megacity of Delhi. Capsule: The study finds that the odd-even driving scheme can help to reduce particulate matter levels compared to non-scheme days at traffic corridors.

The present study undertake an assessment of human health risk regarding mortality and morbidity induced by multiple air pollutants prevailing at 36 transport corridors of the National Capital Territory (NCT) of Delhi, India. The study, covering PM10, PM2.5, SO2 and NO2, utilized the Risk of Mortality/Morbidity due to Air Pollution (Ri-MAP) model in a bid to assess the direct health impacts in the year 2016. The World Health Organization (WHO) guidelines were used to calculate mortality and morbidity for the population in 4 km2 grid sizes in the vicinity of all transport corridors and the results indicate that aggravated by the vehicular traffic, the highest number of excess cases of relative excess mortality respiratory, cardiovascular and total mortality were reported at ISBT Flyover (365, 1399 and 2136), closely followed by Wazirabad Road (362, 1378 and 2096) respectively. These two transport corridors also recorded a maximum number of excess cases of morbidity regarding hospital admission due to COPD (Chronic Obstructive Pulmonary Disease) and cardiovascular illness as 18,979 and 4762 as well as 18,969 and 4761 respectively. Further, excess numbers of cases were reported in 4 km2 grid sizes alongside the transport corridors throughout the megacity of Delhi, thereby presenting a very plausible scenario of traffic-induced human health risk in different residential and other areas. Such studies with a more focussed approach would help not only towards a better transport corridor planning but also help health institutions to be preferable to control excess number of such peculiar health cases in the city and elsewhere.

Air Pollution in India is a major issue with the majority of Indian cities having very poor air quality and reeling under severe particulate pollution. Comprehensive monitoring of air pollution is necessary to counteract this great environmental health hazard. The aim of this study is to develop a multispectral empirical model to estimate the concentration of particulate matter less than ten micrometres (PM10) using Landsat 8 Operational Land Imager (OLI) satellite data over Delhi, India. PM10 concentration data provided by the Central Pollution Control Board from the ground monitoring stations in New Delhi was obtained corresponding to the acquisition date of Landsat 8 satellite data. Atmospheric reflectance in the visible bands of Landsat 8 imagery was calculated and correlated with the PM10 measurements from ground stations. The feasibility of the proposed algorithm was analysed based on the correlation coefficient, and the root mean square error value. The results show that the suggested multispectral PM10 model can predict particulate matter concentrations with an acceptable level of accuracy.

The present study investigates the particle number concentrations and size distributions in the ultrafine and fine-sized regimes over a polluted megacity, New Delhi (28.75° N, 77.12° E), India. The experiments were conducted during the periods (April–May 2020) of strict social and travel restrictions (lockdown) imposed by the Government of India aiming to contain the spread of Coronavirus Disease 19 (COVID-19) pandemic. The different phases of the COVID-19 lockdown witnessed restrictions of varying magnitudes with the significant cessation of anthropogenic sources, viz., industrial, road, railways, and air traffic emissions. Using this unique opportunity, the impact of varying urban emissions on particle number size distributions and new particle formation events were examined. The mean total number concentrations were in the range of ~ (2–3.5) x 104 cm−3 and depicted a gradual increase (~26%) with progressive unlock of the anthropogenic activities. At the same time, accumulation particle concentrations were doubled. However, ultrafine particles (UFP) (diameter

The study inspects the traffic-induced gaseous emission dispersion characteristics from the urban roadside sites in Delhi, India. The concentration of pollutants viz. CO, NO 2 and SO 2 along with traffic and ambient atmospheric conditions at five selected local urban road sites were simultaneously measured. A developed General Finite Line Source Model (GFLSM) was used to predict the local roadside CO, NO 2 and SO 2 concentrations. A comparison of the observed and predicted values emission parameters using GFLS model has shown that the predicted values for SO 2 , CO and NO 2 at all the selected local urban roadside locations are found to lie within the error bands of 5%, 6%, and 7% respectively. A high level of agreement was found between the monitored and estimated CO, NO 2 and SO 2 concentration data. From the study, it has also been established that the developed model exhibits the capability of reasonably predicting the characteristics of gaseous pollutants dispersion from on-road vehicles for the urban city air quality.

Realizing the dominance of petrol-driven passenger cars of MUL over the fleet of cars in India, a case study of different models of petrol-driven passenger cars of Maruti reporting at an authorized service station of M/s R.K.B.K. Automobiles, Gorakhpur was taken up and the tailpipe emissions along with individual vehicle-related parameters were monitored for idle and fast idle test conditions. The outcome of the study relating to the effect of various vehicle-related parameters on CO and HC emissions of petrol-driven passenger cars of Maruti has led to the useful inferences, which can be used not only for predicting the emission of vehicles with respect to vehicle age and mileage, but also for automobile manufacturing sector to help them produce such environmentally benign petrol-driven passenger cars having long-lasting compliance of pollution control systems with respect to vehicle age and mileage of the petrol-driven passenger cars in the country.

The present study undertakes to understand the spatial influence of traffic-induced criteria air pollutants and associated health risks assessment at major transport corridors in Delhi. The study includes the classification of vehicular pollutants parameters into five different distribution categories, i.e., low, moderately low, moderate, moderately high, and high. Spatial distribution maps were developed using Geographic Information System (GIS) environment for eleven districts covering 36 transport corridors of the city. The study demonstrated the concentration of three out of the five ambient air pollutants, namely, NOx, PM10 and PM2.5, with highest values in the range of 294.10–362.57, 203.99–422.42 and 333.71–541.72 μg/m3, respectively. Corresponding National Ambient Air Quality Standards (NAAQS) values were found to be grossly violated as reflected by NOx, PM2.5 and PM10 concentrations with 2–5 times higher values. Remaining two (CO and SOx) were found to be under permissible limits, and most of them exhibited low levels of observed concentrations. The ambient air quality in south, central, east, and New Delhi areas were found to be in high and moderately high categories and necessitating adequate control measures. The study reported a total of 281107, 20791, 31636 expected cases of human exposure to respiratory mortality, cardiovascular mortality and total mortality, respectively whereas, 281107 and 71608 number of cases were reported in relation to respiratory morbidity in terms of COPD hospital admission and cardiovascular morbidity along the transport corridors. The outcome of the study may provide a basis for decision makers to formulate the policy as per the scale of impact of traffic induced air pollution in critical areas around the major transport corridors.