Delhi’s metro system is the first in the world to bag a gold standard for energy efficiency under a global carbon scheme.

The Delhi Metro Rail Corporation (DMRC) which runs one of the biggest metro networks in India rolled out energy efficiency measures in 51 station buildings.

The metro’s bustling network of 142 stations carries 1.8 million passengers on average every day.

The Indian railway operator improved the heating, ventilation and air conditioning and put in more efficient lighting amongst other efforts at a third of its stations to cut electricity use and steam-roll its carbon emissions by 25%.

It is now registered with The Gold Standard Foundation which was set up by charity WWF and sells carbon credits to businesses around the world.

The Gold Standard registration will help Delhi Metro earn around 7000 Voluntary Emission Reduction credits each year for the next decade, with the first credits expected to be issued in four months.

It expects to earn €4-5 for its credits, compared with the current UN rate for one carbon credit which is only 70 cents.

Adrian Rimmer, CEO of The Gold Standard Foundation said: “To date, the transportation sector has not been able to adequately access carbon finance either through voluntary or compliance markets.

“This approval paves the way for other transport systems — not just in developing nations — but also in the developed world to use carbon finance for low carbon development through Gold Standard Certification.”