NEW DELHI: As India looks to increase its testing capacity, the Union health ministry has given its approval to six firms, including three desi companies, to develop commercial Covid-19 test kits that analyse nasal and throat swabs to arrive at a diagnosis within 24 hours. The firms include three Indian companies — Huwel Lifesciences ( Telangana ), Kilpest ( Madhya Pradesh ) and Mylab (Pune) — and two South Korean firms, S D Biosensor and Seegene.A senior government official said that 18 more firms will be named by the end of this week.He added that until now real-time polymerase chain reaction (RT PCR) test kits for diagnosis of Covid-19 were being procured from the US by the Indian Council for Medical Research-National Institute of Virology (ICMR-NIV). They were then distributed to private and government-run testing laboratories.The ICMR and NIV in Pune has completed evaluation of 24 Covid-19 testing kits.