India's first diesel hydrodesulfurisation unit to reduce sulfur content in diesel was commissioned in June 1999. A methyl tertiary butyl ether unit was commissioned in September 1999 to eliminate lead from motor fuels. The facility conceptualised and commissioned South Asia's largest centralised effluent treatment plant by dismantling the four old ETP's (Effluent Treatment Plant) in June 1999. By September 1999 with the commissioning of an atmospheric distillation unit, Gujarat Refinery further augmented its capacity to 13.7 million tonnes per year making it the largest public sector undertaking refinery of the country.