This is more than 90 times the level considered safe by the World Health Organisation and 15 times the Indian government’s norms. The Indian city of New Delhi has closed schools, halted construction and ordered that all roads be doused with water to settle dust in order to combat crippling air pollution. A coal-fuelled power plant on the edge of the city would shut for 10 days.The last week was already one of constant grey smog. It was forced a 10-day ban on the use of diesel-powered electricity generators, except at locations like hospitals and phone towers. Millions, especially children and older people, have respiratory problems. The city has twice imposed a two-week period in which cars were allowed on the roads only on even or odd days and now the number the cars on the streets will be reduced again.