Medical workers help a protester in pain from tear gas fired by policemen on a street in Hong Kong, Sunday, July 21, 2019. Hong Kong police have thrown tear gas canisters at protesters after they refused to disperse. Hundreds of thousands of people took part in a march Sunday to call for direct elections and an independent investigation into police tactics used during earlier pro-democracy demonstrations. Police waved a black warning flag Sunday night before lobbing the canisters into a crowd of protesters. (AP Photo/Bobby Yip), APTOPIX