BEIJING — The father of a 3-year-old boy who died this week from carbon monoxide poisoning in northwest China said strict Covid-19 policies “indirectly killed” his son by causing delays obtaining treatment, in a case that has set off social media outrage. The boy’s death on Tuesday is the latest incident to generate blowback over China’s strict zero-Covid policy, with one critical hashtag racking up 380 million reads on Wednesday on the Twitter-like Weibo platform. “I personally think that he was indirectly killed,” the boy’s father, Tuo Shilei, told Reuters by phone from the Gansu provincial capital, Lanzhou, which has...