"It is not recommended that expatriates travel alone at night (in New Delhi)", says the World Wide Cost of Living Survey conducted by the Economist Intelligence Unit.

The survey studied the cost of living in 13 global capitals based on five parameters: monthly rent for a two-bedroom flat, dinner for two, running a car for a year, cost of a litre of milk and baby-sitter for an hour.

The cities are Los Angeles, London, Paris, Moscow, New Delhi, Beijing, Rome, Nairobi, Tokyo, Washington, New York, Johannesburg and Sydney.

On each of the parameters, New Delhi recorded the lowest cost of living. The cost of baby-sitting in New Delhi was 97 pence per hour, whereas it ranged from 11.47 pounds per hour in Tokyo to 6.65 pounds in London.

The survey reveals that Tokyo remains the world's most expensive city. It also says that the euro strengthening against the dollar has increased the cost of living in many European societies.

The survey records a striking variation in prices across cities: a litre of milk costs 22 pence in New Delhi and 84 pence in Rome. The rent of a two-bedroom flat in London is just above 1,000 pounds while the same flat in Tokyo would cost at least three times more.

The survey reveals for the first time that London is no longer the European Union's (EU) most expensive city. It has been overtaken by Paris and Copenhagen while Lisbon is the cheapest city in the EU.

The survey, aimed at the international business community, suggests that Tehran is the world's cheapest city in the world. Its cost of living is less than a quarter of Tokyo's.