BS III Petrol and BS IV diesel vehicles can run in Delhi again

Several residents have raised an issue with the restriction over the past few days, stating that since their vehicles were less than 15 and 10 years old, respectively, the restriction was unfair.

CAQM had invoked Stage III restrictions on November 2 as air pollution worsened, ordering a halt on non-essential construction work, stone crushing and mining in the region.

After rain and a slight increase in wind speed, Delhi AQI stood at 275 — in the poor range — at 9 pm.

According to the forecast, the AQI is expected to worsen to very poor on Wednesday.

The air quality forecasts by the India Meteorological Department/Indian Institute of Tropical Meteorology do not indicate the average air quality of Delhi to move to ‘severe’ category in the coming days for which forecast is available, the CAQM said.

Why didn’t Delhi see a marked improvement in AQI despite Monday’s rains?

Delhi’s AQI on Tuesday morning was 352 despite the rain on Monday. This, IMD officials said, was because the three factors crucial for a fall in pollution levels were not present. “One is high temperatures, more than 30 or 32 degree Celsius, which will allow air to rise and facilitate vertical dispersion. But temperatures are not high,” said an official.

The maximum temperature on Tuesday was recorded as 22 degrees Celsius, four degrees below normal. The minimum was 14.2 degrees Celsius, four degrees above normal, due to overcast conditions.

“For the dispersion of pollutants, we also need a wind speed of more than 10 kmph. Wind speed this afternoon is only around 4 to 5 kmph. There was an increase in wind speed on Monday, but only for a few hours. The third factor is significant rainfall. There was only a drizzle or light rainfall, and with that dispersion didn’t take place, which is why air quality has remained ‘very poor’,” added the official.