India reported its largest daily increase of COVID-19 cases on Sunday since the pandemic struck the subcontinent in late January.
With nearly 25,000 new cases in the past 24 hours, it is on the verge of overtaking Russia as the third worst-affected country in terms of total coronavirus patients.
India has so far recorded over 673,000 cases of COVID-19 and more than 19,000 deaths.
New Delhi, the country's capital, has begun treating patients in a spiritual centre that has been converted into a quarantine shelter and medical facility with around 10,000 beds, many of which are made of cardboard.
The venue, which is the size of twenty football fields, will be used to treat patients with mild symptoms.
The government is concerned that half a million people could be infected in New Delhi by the end of July. So far, 97,000 have contracted the virus in the capital, according to a Johns Hopkins Coronavirus Resource Center tally.
Along with New Delhi, located in the north, Bombay in the country's west and Chennai in the southeast are India's worst-affected cities.
Schools, metro stations, cinemas, sports venues and swimming pools remain closed in the country and international flights have been halted, but some business activities have resumed.
The Indian Council of Medical Research, the agency leading the country’s COVID-19 response, hopes to develop a vaccine by August 15 - India’s independence day - and asked clinical trial investigators to enrol participants by July 7.
But the WHO’s chief scientist, Soumya Swaminathan, said in an interview with India’s online newspaper The Wire that it is more realistic to expect some phase 1 results to be available by August.