India, Oct. 10 -- People in the national capital breathed the cleanest air in five years for a day that falls immediately after Dussehra, environment monitoring officials said on Wednesday, but warned that the situation is likely to deteriorate in less than a week.

The celebration of Dussehra includes the burning of towering effigies and fireworks, and has been followed by a spike in air pollution at a time when meteorological factors and farm fires in neighbouring states usually turn Delhi's air unfit for breathing.

Central Pollution Control Board (CPCB) data showed that on Wednesday, the city's overall air quality index (AQI) was recorded at 173 compared to 326 last year (see box).

To be sure, when Dussehra falls is also linked to ho...