It began as a trickle, then became a flood of complaints about the foul smell from Hong Kong’s Ta Kwu Ling landfill, 2km from Shenzhen, across the border. Over two months, Hong Kong leader John Lee Ka-chiu’s maiden account on Weibo, China’s Twitter-like microblogging site, has attracted mostly friendly comments, but some unhappy messages began turning up. “Chief Executive Lee, come to Liantang to smell the Hong Kong-produced toxic, stinky scent we smell every day,” wrote Weibo user Jenny, referring to the area in Shenzhen where she lived. Another user, “King of Small Beans”, asked: “Was it mutual respect when...