Festive week: Dense fog in Capital, traffic choked on hill roads

The festive cheer that comes with the week between Christmas and New Year once again brought with it two familiar sights to Delhi and the picturesque hill states that surround it a dense fog enshrouded the Capital, reducing visibility and impairing flight operations even as pollution levels remained uncomfortably high; and hundreds of thousands of tourists thronged towns in Uttarakhand and Himachal Pradesh, causing serpentine traffic snarls on streets, highways and tunnels.

In Delhi, the season's first dense fog brought visibility at the Indira Gandhi International Airport (IGIA) to zero metres between 5.30am and 9.30am, forcing officials to divert seven flights to Jaipur and one to Ahmedabad. As the smog smudged silhouettes across the city, the air quality index (AQI) was in the "very poor" range, breaking the three-day "severe" but staying well over safe limits. The minimum temperature was 7.8°C, largely unchanged from the previous day, but the maximum rose to 25.9°C, five above normal for this time of the year.

The India Meteorological Department (IMD) classifies a fog as shallow when the visibility is between 500m and 1,000m, as moderate fog when it is between 200m and 500m, and as dense when the visibility plunges below 200 metres. The agency predicted that another "dense to very dense" fog will wrap Delhi and large swathes of northwestern India on Tuesday and Wednesday mornings, with temperatures unlikely to dip in this time.

However, an oncoming spell of rain is likely to bring the region showers on New Year's Eve and New Years' Day, said IMD.