The culture of stiff collar and smart suits in summer might be over at the United Nations as it ratchets up thermostat on weeks days and completely shuts down the air-conditioning during weekends to help reduce greenhouse gas emission and save USD one million.

Unveiling the "Cool UN" initiative, the world body advised diplomats, staff and journalist to wear lighter clothes as the air conditioning temperature would be raised from 22 to 25 degrees centigrade from August one.

The UN could save one million US dollars annually if the experiment is successful.

If the one month trial is successful, the United Nations intends to reduce the heating temperature also which would make the headquarters comparatively cooler in winter. Asked for their comment, diplomats demurred but said they would accept the higher temperature.

"We have succeeded in moving climate change to the top of the international agenda for action, and this means that the UN must take action itself," said Ban.

The one-month-long trial during August is expected to cut the UN's carbon dioxide emissions by 300 tons, a 10 percent reduction in energy consumption for the air conditioning systems. This will also result in savings of more than $100,000 by cutting back on the use of steam by over 4,000 million pounds. 

The headquarters system uses steam provided by local energy company for both air-conditioning in summer and heating in winter.

As part of "Cool UN," the Secretary-General is encouraging both personnel and delegates to dress less formally, including by having men leave their ties off.