Updated on: October 18, 2025 | 7:55 PM IST

New Delhi — The national capital continued to battle deteriorating air quality for the fifth consecutive day on Saturday, coinciding with the festival of Dhanteras. According to data released by the Central Pollution Control Board (CPCB), Delhi’s Air Quality Index (AQI) was recorded at 268, placing it firmly in the ‘poor’ category. The persistent haze over the city reduced visibility and raised public health concerns as residents prepared for Diwali celebrations set to take place in two days.

Officials identified PM10 and PM2.5 — fine particulate matter capable of penetrating deep into the lungs — as the dominant pollutants in Delhi’s air. Photographs from across the capital showed a thick layer of smog blanketing popular areas, including Connaught Place, India Gate, and the Delhi-Noida border, indicating the growing severity of pollution in the region.

The trend of worsening air quality has continued throughout the week. On Friday, October 17, Delhi’s AQI stood at 254; on Thursday, it was 245; on Wednesday, 233; and on Tuesday, 211. Prior to this period, the city’s air was categorised as ‘moderate’. Environmental experts have attributed the consistent rise in pollution levels to seasonal weather changes, vehicular emissions, industrial activity, and the early onset of stubble burning in neighbouring states.

While Delhi’s AQI remained ‘poor’, neighbouring Ghaziabad registered the highest pollution levels in the National Capital Region (NCR). The city’s AQI was recorded at 324, categorised as ‘very poor’, making it the most polluted location in the region on Saturday. CPCB data showed that Ghaziabad’s air quality had already been in the ‘very poor’ range for the previous two days, with AQI readings of 306 on Friday and 307 on Thursday.

The CPCB classifies air quality on a six-tier scale — an AQI between 0–50 is considered “good”, 51–100 “satisfactory”, 101–200 “moderate”, 201–300 “poor”, 301–400 “very poor”, and 401–500 “severe”.

Environmental authorities have warned that pollution levels are likely to worsen as the Diwali weekend progresses. The Air Quality Early Warning System (AQEWS) for Delhi forecasted that the city’s air quality would remain in the ‘poor’ category from Saturday to Sunday and may deteriorate further into the ‘very poor’ range on Monday if additional emissions from firecrackers occur. “The air quality is very likely to be in the upper end of the very poor category on Monday in case of additional emissions from firecrackers. The outlook for the subsequent six days suggests the AQI will stay poor, possibly reaching the higher end of the very poor category by Tuesday,” the AQEWS statement read.

Officials and environmentalists have urged residents to exercise restraint in lighting firecrackers during Diwali celebrations, warning that even a moderate increase in emissions could push air quality into the ‘severe’ range. Similar patterns have been observed in previous years when post-Diwali pollution led to thick smog and hazardous conditions across the capital.

Meanwhile, meteorological conditions have remained largely stable. According to the India Meteorological Department (IMD), Delhi recorded a maximum temperature of 33.5°C and a minimum of 19.6°C on Saturday. The IMD has predicted shallow fog or smog during the early morning hours of Sunday in several parts of the city, conditions that may further trap pollutants near the surface and worsen air quality.

Health experts have cautioned residents, especially children, the elderly, and those with pre-existing respiratory conditions, to limit outdoor activities and wear protective masks when venturing outside. The Delhi government has also advised citizens to use public transport where possible and avoid burning waste or biomass — activities that contribute significantly to local pollution levels.

As the festival season continues, authorities are keeping a close watch on pollution indicators. The Delhi Pollution Control Committee (DPCC) has reportedly intensified monitoring and enforcement drives to ensure compliance with anti-pollution measures. Water sprinkling on roads, bans on construction dust, and restrictions on diesel generator use have been reintroduced in several districts.

Despite these interventions, experts fear that meteorological factors such as low wind speed and temperature inversion could worsen the situation over the coming week. With Diwali just two days away, the capital’s air quality trajectory remains concerning, underscoring the urgent need for collective responsibility and stricter enforcement to prevent another post-festival smog episode.