In an attempt to curb pollution levels in the Indian capital of Delhi – the most polluted city in the world, according to the World Health Organization – authorities are trialling a ‘rationing’ experiment which allows certain cars in the city on different days.

Under the trial private vehicles with even and odd number plates are allowed to enter the city on alternate days. The trial began on 1 January and will run for two weeks, after which the government will decide whether to extend or scrap the scheme.

The method is commonly known as ‘road space rationing’ and exists in various forms in many parts of the world.