Delhi might be paying the steepest price for its air pollution with life expectancy dropping by 6.4 years while Uttar Pradesh and Maharashtra are likely to account for the highest number of premature deaths in India, a study by the Indian Institute of Tropical Meteorology has revealed. Conducted by IITM scientists in collaboration with the National Centre for Atmospheric Research (NCAR), Colorado, the study is likely to further ignite concern over the need to improve air quality in the capital and urgently map its sources of pollution and their contribution to making Delhi an unhealthy city .The study is based on data compiled in the 2011 census to arrive at the figures of “premature mortality“ due to exposure to particulate matter across the country .The study found that life expectancy in Maharashtra dropped by 3.3 years due to exposure to pollution. The report, titled `Premature Mortalities due to PM2.5 (finer particulate matter) and Ozone Exposure in India', states that Maharashtra recorded 10% of the country's deaths due to pollution with UP topping at around 15%.IITM scientist Sachin Ghude, who was involved in the study , said, “Although these results are in line with other global estimates, such as the World Health Organization (WHO) and the Global Burden of Diseases (GBD), there's no physical way to tell who has actually been killed by air pollution.“Ghude added, “The methods used in this study rely on statistical algorithms to construct estimates about a population's response to pollution exposure using previous concrete observations on pollution and public health.“The problem is that most of these observational studies have taken place in regions with comparatively low pollution levels, such as Europe or the US, and we don't have any epidemiological studies in India that look at the long-term effects of air pollution on mortality,“ Ghude added. West Bengal (9%) and Bihar (8%) follow Maharashtra.Other states with high premature mortalities due to PM2.5 are Andhra Pradesh Tamil Nadu , Gujarat, Karnataka, Madhya Pradesh , Orissa and Rajasthan, which collectively account for 32% of the countrywide premature mortalities. The research also calculates mortalities due to exposure to harmful ozone (O3) pollution, where Maharashtra stands fourth with 7% of the country's deaths after UP (18%) , Bihar (11%) and West Bengal (9.5%).The report cites PM2.5, which experts say is mostly emitted by vehicles, as the cause for chronic pulmonary diseases.The scientists extrapolated data of the country's population figures at the time from globally released figures of pollution.This included satellite analysis and development of the country's own simulation models. The study was published in the journal, Geophysical Research Letters (GPL), last week.Ghude said, “Premature mortalities due to PM2.5 is 5.7 lakh and from ozone 12,000 for 2011. Exposure to these led to an economic loss of approximately $640 billion. Exposure to fine particulate matter in the air also reduces life expectancy by about 3.4 years.“Doctors emphasize that regular exposure to such pollution drastically affects people's health.“Air pollution of finer matter also enters the heart apart from the lungs through the blood stream and causes ischaemic heart disease, heart attacks and blood pressure problems,“ saidSundeep Salvi, director of the Punebased Chest Research Foundation (CRF).Apart from Ghude, others from IITM involved in the study were D M Chate, C Jena, Gufran Beig, S Fadnavis and Prakash Pithani.