Geneva: The World Health Organisation (WHO) said that only one strain of the Covid-19 Delta variant first detected in India was now considered 'of concern', while two other strains had been downgraded.
The B.1.617 variant of the virus, which has in part been blamed for India's explosive outbreak, has been dubbed a triple mutant variant since it is split into three lineages.
The UN health agency last month declared the entire strain a 'variant of concern', or VOC, but on Tuesday, it said only one of the sub-lineages deserved that label.
"It has become evident that greater public health risks are currently associated with B.1.617.2, while lower rates of transmission of other lineages have been observed," the World Health Organization said in its weekly epidemiological update on the pandemic.
The B.1.617.2 variant remains a VOC, along with three other variants of the virus that are seen as more dangerous than the original version because they are more transmissible, deadly or have the potential to get past some vaccine protections.