What grade of fuel did Indian Oil Corporation (IOCL) introduce in 2019?

The Indian Oil Corporation (IOCL) has stated that Supply of ultra-clean BS-VI grade petrol and diesel has begun in cities adjoining the national capital. The rest of the country will follow suit from April 2020. New Delhi is the first city in the country to leapfrog from BS-IV grade petrol and diesel to BS-VI fuels. Bharat Stage norms are standards set by the government to regulate the emission of air pollutants from motor vehicles. The norms set the limit for the release of air pollutants such as nitrogen oxides, carbon monoxide, hydrocarbons, particulate matter (PM) and sulphur oxides from vehicles using internal combustion engines. The Bharat stage norms are based on Euro norms. BS-IV fuels contain 50 parts per million (ppm) sulphur whereas BS-VI grade fuel only has 10 ppm sulphur.