India had earlier invited leaders of all member-countries for the summit - the first under its presidency - that will be chaired by PM Narendra Modi. An in-person summit would have seen Modi coming face-to-face with both Xi and Sharif at a time ties with China have been wrecked by the boundary dispute and when the relationship with Pakistan is nearing rock bottom.
source https://timesofindia.indiatimes.com/india/amid-strife-in-china-pakistan-ties-india-to-host-virtual-sco-meet/articleshow/100631528.cms
source https://timesofindia.indiatimes.com/india/amid-strife-in-china-pakistan-ties-india-to-host-virtual-sco-meet/articleshow/100631528.cms