DELHI AND KOLKATA HAS BEEN FOUND TOP TWO MOST-POLLUTED CITIES INTHE WORLD .

North India emerged as the most polluted region in the country in summer of the year with Delhi NCR being the hotspot, According to a news analysis by the centre for science and environment It is stated that the average PM 2.5 concentration in the north india in summer stood at 71 microgram per cubic metre.It was 69 microgram per cubic metre in the east India, 54 microgram per cubic metre in the west India and 46 microgram per cubic metre in the central India.The northeast India has been found 35 microgram per cubic metre and the south india 31 microgram per cubic metre has been found cleaner to other regions.It said that the north india Delhi-NCR was found to be the most polluted sub -region with Bhiwani (Haryana) reporting the highest average PM2.5 concentration of 134 microgram per cubic metre,where as the PM2.5 summer average of Delhi-NCR region is almost three times the average of the cities in southern India. As per the latest report on the air quality in the cities around the world Delhi and Calcutta ranked highest in pollution due to fine particulate matter.The US based research organisation health effects Institute Report focused on the two of the most dangerous pollutants ie fine particulate matter (PM2.5) and the nitrogen dioxide (NO2) .When the PM2.5 levels were compared , Delhi and Calcutta were found to be the top two most polluted cities in the world,with an average annual exposure of 110 meu g/ cubic metre for Delhi and 84 for Kolkata.