After a week of breathing in the world's most polluted air plume, Chennai can now heave a sigh as the haze has subsided. Easterly- and North-easterly winds, which had steered clear of the land due to cyclone Bulbul, have returned after the dissipation of the cyclone.
After the metropolitan city woke up to unprecedented thick smog last week, it was discovered that the pollution plume over north India, which concentrates especially around the very-polluted Delhi, had moved southward as the low-pressure system in the Bay of Bengal began drawing the winds out. Even as the government rubbished the theory of moving pollution plume, claiming the haze to be the cyclone's doing, private players and even the European Union Earth Observation Programme tweeted confirming the movement of the pollution plume.
After consistently recording PM2.5 levels higher than Delhi for over three days, air quality measurement centres around Chennai recorded PM2.5 levels under 100 on Tuesday, marking the return of normalcy. On Wednesday, the PM2.5 level at Alandur was 90, falling dramatically from Sunday's measured level of 249. Chennaites, who have been lamenting the visible haze, have been posting joyous message on the social media about been able to see clear skies again. The city is having a week of cloud cover and the relative humidity is at 74% today. There is a trend of the cloud cover increasing towards the evening and night rains are expected to resume this weekend.
According to forecasts, there will be light rain in the Delta and in the Ghats around Theni district. Chennai is to miss rains for the day, but the prospects of the week look promising.