Prime Minister Narendra Modi landed in Guwahati for a two-day tour of the Northeast on Friday evening, only to be greeted with black flags and angry activists protesting the controversial Citizenship Amendment Bill. Several civil society groups across the Northeast -- including the All Assam Students Union -- have decided to intensify their ongoing agitation in view of PM Modi's visit, which will include public rallies and foundation-laying ceremonies across Arunachal Pradesh, Assam and Tripura.