The strikes on Friday came as new satellite photos appeared to show a massive convoy outside the Ukrainian capital had fanned out into towns and forests near Kyiv.

"We see a really clear association between how these maps were drawn in the '30s and the air pollution disparities today," says an author of a study on the effects of the discriminatory policy.

A roundup of key developments and the latest in-depth coverage of Russia's invasion of Ukraine.

As cryptocurrency become more mainstream, some states are introducing legislation to standardize crypto as a form of payment.