India's top oil and gas producer ONGC will invest Rs 1 lakh crore by 2030 on energy transition projects as it targets net zero carbon emissions by 2038, its chairman Arun Kumar Singh said on Monday. The firm joins fellow state-owned oil and gas firms Indian Oil (IOC), Hindustan Petroleum (HPCL), GAIL and Bharat Petroleum (BPCL) in preparing roadmaps for net zero emissions as part of the nation's commitment to deal with the climate challenge.