this is bbc world news. i m lukwesa burak. our top stories. the olympic host nation, japan, has picked up its first medals winning gold and silver injudo. that was after ecuador s richard carapaz won the gold in the men s cycling road race, making it the country s second ever top medal at a summer olympics. a night time curfew has come into force across most of afghanistan, in an attempt to stop the taliban infiltrating its cities. we hear from an afghan politician. it s to help keep the citizens of afghanistan safe, and if you haven t noticed, there s going to be a huge exodus of refugees because of the fear that the taliban bring to us. the uk government changes its policy on covid isolation for more key workers as tens of thousands of daily infections