Those who wish to know the level of air pollution in their neighbourhood will now be able to get the data at the click of a mouse. Prime Minister Narendra Modi launched the initiative on Monday. The data is available for Chennai from March 25 onwards at . The idea behind the launch of online data is for people to change the lifestyle by looking at the AQI of their neighbourhoods.

Everyday, the site will show maximum, minimum and average levels for all the four pollutants. In the coming days, other pollutants like particulate matter up to 10 micrometre, Ozone, ammonia and lead levels will also be displayed.

All indicators are classified as good, satisfactory, moderately polluted, poor, very poor and severe and are given colour codes for people to understand. The site also gives a possible health impact for each of these categories. For example, good has minimal impact, while moderate would make breathing uncomfortable for people with asthma and heart and lung diseases. If the locality is marked severe, it would affect even healthy people.

Though data from the site is inconsistent, Chennai does not seem to be doing well as per the data provided. Last Wednesday, the AQI in Manali, an industrial hub was 237 and was classified as poor. Alandur, which is residential area, got an AQI of 88, which was classified as good. The site also gives the most prominent pollutant of the day.

While gaseous pollutants indicated high vehicular pollution, particulate matter indicated mixture of both vehicular and industrial emissions. According to a study by IIT-M done, vehicles contributed for 14% of particulate matter and 68% of nitrogen oxides.

While Chennai is considered clean compared to other big cities, environmentalists say there is no reason to celebrate. Sea breeze, they say, is the saving grace as it flushes out most pollutants. "Given its vehicular population, pollution levels in the city would have been much higher. The sea breeze lowers the peaks," said Anumita Chaudhary.