After a brief lull, pollution in city again in severe zone

ALARMING Experts say low wind speed and high moisture levels have pushed pollution up

NEW DELHI : Delhi is on the brink again. The city is plunging into severe levels of air pollution once again, more than a fortnight after it was engulfed by a week-long haze in November.

Monday’s average Air Quality Index of Delhi shot up to 390 from 351 on Sunday. An AQI value above 400 on the scale of 500 is considered as severe pollution. Such high levels of pollution were last seen on November 14 when the city had just come out of the week-long haze.

“Even though the average AQI is yet to hit severe levels, several monitoring stations in the city such as Shadipur, RK Puram, Anand Vihar, Siri Fort and CRRI had already entered the severe zone,” said a senior official of the Delhi Pollution Control Committee.

The levels of particulate matter - the dominant and one of the most dangerous pollutants – also shot up to alarming levels. At around 7 pm on Monday, the levels of PM10 and PM2.5 had already shot up around 4.5 times the safe standards.

While PM concentration had touched 448ug/m3 around 7 pm, the level of PM2.5 had soared to 272ug/m3.

According to the Graded Response Action Plan, if the level of PM10 and PM2.5 hits the 500 and 300-mark respectively and stays there for at least two days, emergency measures such as road rationing, shutting down of schools and ban on construction activities would be introduced.

Experts said that it is because of the adverse meteorological conditions that pollution levels have spiked again.

“The low wind speed and high moisture levels in the air have pushed up pollution levels. While on one hand the moisture is trapping the pollutants in the air, the calm winds are not being able to flush out the pollutants. Pollutants are accumulating,” said D Saha, head of the air quality laboratory at CPCB.

The regional weather forecasting centre at New Delhi has forecast that there could be light rain on Wednesday. Monday’s partially cloudy sky was a prel- ude to the coming rains.

“An outflow of the cyclone has reached northwest India. This is likely to trigger some light rain or drizzle on Wednesday. There could be some thunder on Tuesday evening. On Thursday we are expecting some shallow fog after which the sky could clear up as winds could pick up speed again,” said Kuldeep Srivasatava, a scientist with the regional weather forecast department.

SAFAR, India’s official pollution forecasting system under the union ministry of earth sciences, has forecast that pollution levels could rise till Thursday.