Tens of thousands of opposition supporters rallied on Sunday in the city of Karachi as part of a campaign to oust Pakistan's Prime Minister Imran Khan, who they accuse of being installed by the military in a rigged 2018 election. Nine major opposition parties formed a joint platform called the Pakistan Democratic Movement (PDM) last month to begin a nationwide agitation against the government. The next general election in Pakistan is scheduled for 2023. Watch report.