Mumbai The closure of the 25-year-old dumping ground measuring 19.6 hectares at the Gorai creek in Borivli has earned the Brihanmumbai Municipal Corporation (BMC) Rs 27 crore by trading of an estimated 31,033 tonnes of carbon credits a year. The Asian Development Bank (ADB) has agreed to purchase the carbon credits from the civic body at a cost of 12 Euros per carbon credit till 2014.