One of Shanghai's main business districts is urging office workers to ditch their suits and ties for shorts and T-shirts Friday as temperatures approach 40 degrees Celsius (104 Fahrenheit).

Shanghai municipal government is starting an 'energy saving' campaign in order to promote the people's awareness of environmental protection, said a notice in the lobby of the Azia Center, in the city's financial hub of Pudong.

It said the building association in Shanghai's financial hub, Lujiazui, and 31 other office buildings decided Friday would be Cool dress day.

The main idea of this proposal is white-collar office staff should go to work dressing comfortably on July 27th to promote environmental awareness, it said.

The government was also calling on office buildings in the area to turn up air-conditioner temperatures to save energy, the Web site reported Thursday.

It said people were being encouraged to wear shorts and T-shirts instead of their usual black or grey suits.

China's sustained, breakneck economic expansion has caused energy demand to balloon, but power capacity is chronically lagging demand and there are frequent power outages in some parts of the country.