Delhi's Air Quality Index Shows Improvement but Remains in Poor Category for Third Consecutive Day

Delhi's air quality remained in the poor category for the third day, offering some relief from severe pollution. On Tuesday, the city's Air Quality Index (AQI) was 268, slightly better than Monday's 280. However, updates from the Decision Support System (DSS), which tracks pollution sources, have been missing since Friday.

The DSS data available only covers November 26 to 29. A Commission for Air Quality Management (CAQM) official mentioned that the system is still being developed and isn't fully operational. The evaluation committee found that the data accuracy didn't meet the required standards. Some information and emissions inventory were outdated, according to an anonymous official.

Pollution Sources and Trends

The DSS last reported on November 26 that stubble burning contributed 5.64% to Delhi's PM2.5 levels, down from 6.99% on November 25. No updates have been provided since then. From November 27 to 29, vehicular emissions were estimated to contribute between 21% and 24.6% to PM2.5 levels, with other sources accounting for between 22% and 24.6%.

Air pollution sources in the NCR region have changed over time, requiring updates to the DSS. The official noted that it's unclear when the system will resume providing data. An IITM representative confirmed that an expert committee is reviewing the tool.

Weather Conditions and Forecast

Tuesday saw a sunny day with a high of 28.2°C, which is 2.9°C above normal, according to the India Meteorological Department (IMD). The minimum temperature was recorded at 10.5°C, slightly above average for this season. Humidity ranged from 96% to 62% during the day.

The Air Quality Early Warning System noted light winds on Tuesday with speeds under 16 kmph until evening, decreasing further at night from the northwest direction. Smog and mist are expected in the evening and night, with clear skies predicted for Wednesday.

Air Quality Monitoring

Out of Delhi's 37 air quality monitoring stations, only five reported very poor air quality on Tuesday; others recorded poor air quality as per the Sameer app. The Central Pollution Control Board (CPCB) classifies AQI levels: good (0-50), satisfactory (51-100), moderate (101-200), poor (201-300), very poor (301-400), and severe (above 400).

The primary pollutants on Monday were PM2.5 and PM10, with PM2.5 at 105 µg/m³ at 3 pm and PM10 at 204 µg/m³ on Tuesday at the same time. These particles pose health risks as they can penetrate deep into lungs and enter the bloodstream.

The forecast predicts northwesterly winds under 10 kmph in the morning on Wednesday, increasing to 12-16 kmph in the afternoon before decreasing again in the evening and night. Smog and shallow fog are expected in the morning.

The weather department forecasts mist for Wednesday with temperatures around a maximum of 26°C and a minimum of 11°C.