India’s capital Delhi recorded its worst November air in at least six years, according to official data, BBC reported.

The city recorded 11 days of “severe” pollution, up from 10 days in November 2016.

Data also showed that the residents of Delhi didn’t experience even one “good” day of air quality through the month.

Experts blame the burning of crop stubble in neighbouring states for the alarming levels of pollution in November.

The numbers are the worst Delhi has seen since 2015, when the Central Pollution Control Board started recording air quality data.

Satellite data from Nasa shows that there were 90,984 fires from stubble burning in three states – Punjab, Haryana and Uttar Pradesh – between October 1 and November 28.

Stubble burning – where crop residue is burnt every year to make way for planting wheat – turns the city’s air toxic every year.