Delhi chokes on ‘very poor’ air, relief unlikely this week

Over the past 24 hours, maximum temperatures fell by 2-5°C while minimum temperatures rose by 2–5°C at many locations. Maximum temperature in different parts of the city hovered in the range of 16°C to 17°C, while minimum temperature ranged between 8°C and 11°C. While minimum temperature was above normal at a few places, maximum temperatures remained markedly to appreciably below normal across most parts of the Capital.

Shallow to moderate fog continued to impact visibility, particularly during night and early morning hours. Safdarjung, the city’s base weather station, recorded visibility as low as 200 metres between 1.30 am and 2.30 am, improving to 500 metres by early morning.

Meanwhile, meteorological conditions remain largely unfavourable for dispersion of pollutants. As per the IITM bulletin, the ventilation index is expected to stay low on Monday, well below the threshold considered conducive for pollutant dispersion.

Low wind speeds, coupled with a shallow mixing layer, are likely to sustain high pollution levels over the city.

The India Meteorological Department (IMD) stated in its daily bulletin that a western disturbance persists. This means that slightly warmer nights are expected due to cloud cover. The maximum temperatures are expected to remain appreciably below normal before returning to near normal levels on Monday and Tuesday, while minimum temperatures are likely to remain above normal for the next two days, it said.

The IMD has forecast partly cloudy skies over the next couple of days, with mist and shallow fog during evening and night hours on Monday, and moderate fog at many places with dense fog at isolated locations in the morning. From Tuesday onwards, shallow to moderate fog is expected to persist during morning hours, with periods of moderate to dense fog later in the week.

According to the latest available data from IITM’s Decision Support System, which was last updated on Saturday, the transport sector remained the single largest local contributor to PM2.5 pollution in Delhi, accounting for 17.57%. Delhi and peripheral industries contributed around 8%, while residential emissions stood at 4.34%.

Pollution inflow from neighbouring regions also continued to play a significant role. Jhajjar was the highest external contributor, accounting for 16.51% of Delhi’s PM2.5 load, followed by Rohtak at 4.3%, Bhiwani at 4.2%, and Gurgaon at around 2%, among other surrounding districts.