Delhi breathes poison: Worst air quality since 2019, SC says don’t lift curbs until orders

Now, five years and dozens of Supreme Court orders later – and despite stringent measures on days when the AQI is in the severe and severe+ zone — Delhi appears to be back to square one.

Nudged by the Supreme Court, which on Monday said physical classes in schools should be suspended, the Delhi government announced that classes for Class X and XII students would move online.

The administrations in Gurgaon and Faridabad also issued orders to suspend physical classes up to Class XII until November 23.

The Delhi University also declared that classes in all colleges will move online, at least until Saturday.

The day started with dense smog, leading to delays for several flights, 15 diversions and 21 cancellations, according to Flightradar24, an online portal that live-tracks flights across the world.

At 11 am, the AQI was 487, with the sun remaining hidden under a blanket of smog. By afternoon, the city bore a sepia tint and the AQI at 2 pm stood at 491.

There has been no marked change in the weather conditions over the past three days, except for a dip in temperature. (Express Photo)

This was unusual because the day’s worst AQI is usually seen in the early morning hours. It improves as the day progresses, with higher temperatures helping in dispersion of pollutants.

There has been no marked change in the weather conditions over the past three days, except for a dip in temperature. According to experts, a small dip in temperature, especially during the day, has a significant impact on the AQI. High humidity, low temperatures and low wind speed aid the accumulation of pollutants.

The maximum temperature Monday was 23.5 degrees Celsius, four degrees below normal. Till last week, Delhi’s maximum temperature was over 30 degrees Celsius.

“Westerly winds have been prevailing at a low speed of 5 to 10 kmph in the last 24 hours. These meteorological conditions are generally observed around this time… In the next 24 hours to 48 hours, there will not be much change in the weather conditions… No rain is expected either. There will only be an improvement if wind speeds increase,” said R K Jenamani, head of IMD’s National Weather Forecasting Centre.

Another IMD scientist said, “These atmospheric conditions are generally observed at this time but the stability in the atmospheric layer because of thermal inversion combined with low wind speed has trapped the pollutants which is why the pollutant concentration has been continuously high.”

With the wind speed remaining under the 10 km per hour mark in recent days, pollutants have only accumulated. The conditions are unfavourable for dispersion. The primary pollutant, as per CPCB, was PM 2.5.

At RK Puram, for example, the concentration was 1,050 microgrammes per cubic metre at 1 pm.The prescribed standard for PM 2.5 is 60 microgrammes per cubic metre.

At India Gate, the PM 2.5 concentration peaked at 969 microgrammes per cubic metre at noon.

According to the Early Warning System for Air Quality in Delhi, no improvement is expected until Thursday and the AQI is expected to remain in the severe or severe+ category.

The predominant surface wind on Tuesday is likely to be coming from northwest directions, carrying a load of particulate matter because of stubble burning, with a speed 08-12 kmph. The wind speed is expected to drop to 02-10 kmph on Wednesday.

Delhi Environment Minister Gopal Rai, meanwhile, said the Delhi government was doing everything to control major pollution sources. Asked about the implementation of odd-even measures, Rai said a decision will be taken based on necessity.

He accused the Centre of inaction and blamed the BJP-led neighbouring states for increasing the vehicular pollution load in Delhi.

“It has been two-and-a-half months since I wrote to the Union Environment Minister to call an emergency meeting for artificial rain. But the BJP government has not done anything… Till now there has been not a single response from the Centre,” Rai said.