The number of Indians who have tested positive for the new Covid strain has gone up to 20. All those found infected with the more infectious mutant strain are UK returnees. The dangerous and fast-spreading strain of Covid-19 was first detected in the UK last month. Authorities have been testing all those arriving from UK for past few days at airports and their samples were analysed at special labs for the new strain. On Tuesday, the govt had said that six of the UK returnees were found infected with the new strain that is believed to be 70 per cent more infectious. All people have been kept in single room isolation, the govt said.