Delhi recorded its most polluted start to October in four years on Thursday, with the average air quality index rising to 166 in the moderate category.

The last time the capital recorded a higher AQI on October 1 was in 2022, when it reached 186, according to an analysis by the Centre for Research on Energy and Clean Air.

Of 44 monitoring stations, 37 recorded moderate air quality, five were poor and two were satisfactory, data from the Central Pollution Control Board showed. IIT Delhi logged 248 and Jahangirpuri 218, both in the poor band.

The dip follows Delhi’s cleanest September in five years, when the monthly average AQI fell to 102. Weak ventilation and stubble burning are blamed for the rise.

The Delhi government has launched an AI-powered command centre to track pollution sources in real time. It will monitor construction sites, road sweeping and open burning.

Work-from-home for half of government and private staff starts November 1. New pollution-under-control certificate rules for fuel purchases took effect on October 1.