Thursday on the NewsHour, more outdoor events are canceled and millions of Americans are warned to stay indoors as eastern states are blanketed by smoke from Canadian wildfires. President Biden meets with the prime minister of the United Kingdom amid challenges in Ukraine. Plus, the head of UNICEF discusses the devastating impact wars are having on children around the world. PBS NewsHour is supported by - https://www.pbs.org/newshour/about/funders