The COVID-19 started from Wuhan city in China, slowly spread across the globe after December 2019. Due to movement of people from one city to other cities, one country to other countries, infection spreads and COVID-19 became a pandemic. Efforts were made at local, regional and national levels to lockdown the movement of people and to keep infected one in quarantine or isolation to stop the spread of COVID-19. The traffic, market and small industries were closed, as a result pronounced decline in the concentrations of particulate matters (PM) were observed. Normally these sources contribute to the high concentrations of particulate matters (PM 2.5 ) which represents air quality of a location. In this short communication, we present analysis of PM 2.5 of major cities (New York,

First time in India, total lockdown was announced on 22 March 2020 to stop the spread of COVID-19 and the lockdown was extended for 21 days on 24 March 2020 in the first phase. During the total lockdown, most of the sources for poor air quality were stopped in India. In this paper, we present an analysis of air quality (particulate matter-PM 2.5 , Air Quality Index, and tropospheric NO 2) over India using ground and satellite observations. A pronounced decline in PM 2.5 and AQI (Air Quality Index) is observed over Delhi, Mumbai, Hyderabad, Kolkata, and Chennai and also a declining trend was observed in tropospheric NO 2 concentration during the lockdown period in 2020 compared with the same period in the year 2019. During the total lockdown period, the air quality has improved significantly which provides an important information to the cities' administration to develop rules and regulations on how they can improve air quality.

Abstract. We present the first Multi-Axis-(MAX-) DOAS observations in India performed during April 2010 and January 2011 in Delhi and nearby regions. The MAX-DOAS instrument was mounted on a car roof, which allowed us to perform measurements along individual driving routes. From car MAX-DOAS observations along closed circles around Delhi, together with information on wind speed and direction, the NO x emissions from the greater Delhi area were determined: our estimate of 4.4 × 10 25 molecules s −1 is found to be slightly lower than the corresponding emission estimates using the EDGAR emission inventory and substantially smaller compared to a recent study by Gurjar et al. (2004). We also determined NO x emissions from Delhi using OMI satellite observations on the same days. These emissions are slightly smaller than those from the car MAX-DOAS measurements. Finally the car MAX-DOAS observations were also used for the validation of simultaneous OMI satellite measurements of the tropospheric NO 2 VCD and found a good agreement of the spatial patterns. Concerning the absolute values, OMI data are, on average, higher than the car MAX-DOAS observations close to strong emission sources, and vice versa over less polluted regions. Our results indicate that OMI NO 2 VCDs are biased low over strongly polluted regions, probably caused by inadequate apriori profiles used in the OMI satellite retrieval.

BackgroundHead and neck cancer (HNC) is the seventh most common type of cancer in the world and constitute 5% of the entire cancers worldwide. The global burden of HNC accounts for 650,000 new cases and 350,000 deaths worldwide every year and a major proportion of regional malignancies in India. More than 70% of squamous cell carcinoma of the head and neck are estimated to be avoidable by lifestyle changes, particularly by effective reduction of exposure to well-known risk factors such as tobacco smoking and alcohol drinking.MethodsA retrospective analysis of 12 years (2001 - 2012) of HNC patients attending RCC, PGIMS Rohtak was done. Total numbers of cancer patients seen were 26,295 and out of these 9,950 patients were of HNCs, which were retrospectively analyzed for their associated risk factors in different HNC subtypes. Most of the patients, i.e. 92.3%, were presented as locally advanced HNC (stages III and IV).ResultsIt has been observed that smoking and alcohol are the strongest independent risk factors responsible for increased risk of HNC and are further having synergetic correlations.ConclusionThe present study confirms the principal role of alcohol consumption and smoking in HNC carcinogenesis, as well as the differential associations with HNC subtypes, and a significant, positive, multiplicative interaction with different risk factors.

Crop residue burning (CRB) is a recurring problem, during October-November, in the northwestern regions (Punjab, Haryana, and western Uttar Pradesh) of India. The emissions from the CRB source regions spread in all directions through long-range transport mechanisms, depending upon the meteorological conditions. In recent years, numerous studies have been carried out dealing with the impact of CRB on the air quality of Delhi and surrounding areas, especially in the Indo-Gangetic Basin (also referred to as Indo-Gangetic Plain). In this paper, we present detailed analysis using both satellite-and ground-based sources, which show an increasing impact of CRB over the eastern parts of the Indo-Gangetic Basin and also over parts of central and southern India. The increasing trends of finer black carbon particles and greenhouse gases have accelerated since the year 2010 onward, which is confirmed by the observation of different wavelength dependent aerosol properties. Our study shows an increased risk to ambient air quality and an increased spatiotemporal extent of pollutants in recent years, from CRB, which could be a severe health threat to the population of these regions.