The level of air and noise pollution is measured every year by the Central Pollution Control Committee. This year certain changes were introduced in measuring methods. Till last year, pollution levels were measured at seven places in the city. These included Sectors 9, 22 and 29 as well as Panjab University, Kaimbwala village, Kajheri village and Manimajra. Measurements were done a day before Diwali, on Diwali day and a day after.

However, this year, measurement were done at three places: Sectors 17, 22 and 29. Measurements were taken a week before Diwali on November 6 and on the day of Diwali.

This year was also the first time that pollution levels at commercial area of Sector 17 were measured where noise level of 67 decibles was recorded. The RSPM level was measured at 207 micrograms per cubic metre (mpcm) as compared to last week when it was recorded at 111 mpcm.

In Sector 29 that is a silence zone, the sound and noise levels recorded were the highest. The sound level was 75 decibel against the permissible limit of 55 decibel. RSPM was recorded as 349 mpcm as compared to 154 mpcm last week. Last year it was recorded as 342 mpcm. Meanwhile in the residential area of Sector 22 the RSPM level was recorded as 280 mpcm as compared to 301 mpcm last year. The sound levels were recorded higher than normal.