XBB was the most commonly circulating omicron sub-variant in the samples collected till the third week of March 2023, the bulletin issued on Thursday said. Is. The bulletin states that Omicron and its sub-variants continue to spread in India and an increase in infection rates has been observed, especially in the western, southern and northern parts of India. It has been said in the bulletin, the emergence of a new variant XBB.1.16 has been observed in different parts of India. Out of the total cases reported so far, .2 percent are of XBB.1..