Delhi's pollution has once again soared to hazardous levels, with a top expert warning that India's toxic air will have a bigger impact on public health than the COVID-19 pandemic.

Axar.az, citing BBC reports that on Wednesday, the air quality was 35 times over the safe limit set by the World Health Organization (WHO), leaving residents complaining of breathing problems, as well as itching in their eyes and throat.

Authorities have urged people, especially children and the elderly, to stay indoors as much as possible, while doctors recommend wearing a mask.

But Frank Hammes, global chief executive of air technology company IQAir, warns this is just a short-term measure - and much more needs to be done.

"This is going to have a much bigger impact on public health than Covid-19," he said.