Pollution

In 2017, Delhi was again enveloped by a thick haze as the air quality remained ‘severe’ for a week. The AQI value touched 486 on November 9, 2017, prompting chief minister Arvind Kejriwal to describe Delhi as a ”gas chamber”, declare a public health emergency, and order that schools be shut.

The city’s AQI was 328 on Wednesday, and on Thursday it worsened marginally to 331 – the highest so far this season. On a scale of 0-500, an AQI value between 301 and 400 indicates ‘very poor’ air quality, and value beyond 401 indicates ‘severe’ pollution.

CPCB’S task force is expected to hold a meeting on Friday to take stock of the worsening situation and the expected spike from November 1 onwards.

Experts have blamed the prevailing pollution level on unfavourable meteorological conditions, including a dip in temperature, low wind-speeds, and a cloudy sky, which are combining to keep pollutants suspended in the air.

These adverse weather conditions are unlikely to improve over the next few days.

“Things are already bad. Add to this, the pollution expected to be triggered on Diwali night now that Supreme Court has relaxed the ban on bursting fireworks. Only favourable wind condition could have brought some respite. But if the weather remains bad, Delhi could be in for another spell of smog in the first week of November,” said D Saha, former head of CPCB’S air quality laboratory.

The Supreme Court on Tuesday set a two-hour window for the use of low-emission firecrackers on Diwali night, but unlike last year, did not impose any ban on the sale of firecrackers in NCR.