NEW DELHI (AFP) - German Chancellor Angela Merkel got a toxic welcome to India on Friday (Nov 1) as Prime Minister Narendra Modi treated her to a military parade in New Delhi in severely polluted air.

Ignoring medical advice issued to the choking megacity's 20 million inhabitants to wear pollution masks, Dr Merkel and Mr Modi reviewed a guard of honour at the presidential palace breathing in the air without protection.

Dr Merkel sat for the national anthems because of her own health problems.

The Indian government monitoring agency rated on Friday the air in the Indian capital, a noxious cocktail of industrial and vehicle emissions and agricultural smoke, as "severe".

Levels of particulates smaller than 2.5 microns, so tiny they can enter the bloodstream, were 19 times the World Health Organisation safe maximum, according to the US embassy website.

India is home to 14 of the 15 most polluted cities in the world, according to the United Nations. According to one study, smog kills a million Indians prematurely every year.

Dr Merkel arrived late on Thursday for a fifth round of inter-governmental talks focused on digitalisation, economy and trade, as well as development and sustainability.