The current wave of the coronavirus pandemic in Delhi could have been fuelled by the UK variant as its prevalence in genomes sequenced nearly doubled from the second to the last week of March, Sujeet Singh, director of the National Centre for Disease Control, said on Friday.

Speaking at a webinar, 'Genome Sequencing of SARS-CoV-19', Singh said the UK variant of coronavirus is also dominant in Punjab.

In Delhi, there are primarily two types of variants -- B.1.617 and the UK strain -- found in the genome sequenced samples, the NCDC director said.

The B.1.617 variant of coronavirus is also known as the double mutant strain.

The UK variant was found in 28 per cent of samples in the second week of March. In the last week of the month, 50 per cent of samples had this variant, Singh said.

"If we try to co-relate, the surge we are observing in Delhi, it directly co-relates to the type of variant which we are observing," he said.

So far, Singh said, 15,133 samples have been sequenced by INSACOG, a consortium formed in December last year to increase viral genomic surveillance in order to understand the spread of the coronavirus in a rapid and robust manner.

This was also after the UK, South African and Brazilian strains, which have a higher rate of transmission, emerged.

Singh said in Maharashtra, the B.1.617 variant was found in proportions of over 50 per cent in many cities.

The NCDC is one of the 10 laboratories involved in the genome sequencing of coronavirus.