MOSCOW—The sudden, unexplained illness of Alexei Navalny comes in the midst of what has been a difficult year for Russia’s leader, President Vladimir Putin. Mr. Navalny has for years been the Kremlin’s most effective critic, with some four million followers on his campaigning YouTube channel. He fell ill on a flight from Siberia to Moscow on Thursday after drinking a cup of tea at the airport that his supporters believe was laced with poison.

Source: Wall Street Journal August 21, 2020 11:42 UTC