The UK strain is behind the rapid rise in coronavirus cases in Delhi, an analysis of samples has revealed. Data released by the National Centre for Disease Control (NCDC) says over 400 cases of the UK strain and 76 of the Indian double mutant were found in Delhi, said reports.

Some 11 per cent samples from across India show "variants of concern", IBNS said. 

A total of 1,644 cases of the UK strain have been found in India, while 112 cases are from the South African strain, one of the Brazilian strain and 732 cases of the double mutant that emerged in India.

Cases of the UK strain almost doubled to 50 per cent in samples from Delhi in March, according to the NCDC laboratory.

"The UK strain directly correlates to the Delhi surge," said Sujeet Kumar Singh, director, NCDC, at a webinar on ''Genome Sequencing of SARS-CoV-19'.

"In Delhi we have a different type of scenario. The UK variant and B 1617 (double mutation) are present. The scenario is still unfolding. But we've seen a rise from 28 per cent of UK variant on March 2 and it has risen to 50 per cent in the last week of March. If we co-relate with the surge, I think it directly co-relates with the type of variant we're observing," Singh explained as quoted by NDTV.

Delhi on Friday logged 348 Covid-linked deaths, its highest-ever single-day spike in the fatality count.

The city also reported 24,331 fresh infections amid the rapid second wave of the pandemic. The national capital currently has 92,000 active cases, which is also a record.