TOKYO -- China and India have increased Russian oil purchases as prices decline due to Western import bans, the latest data shows, creating a loophole that allows Moscow to secure export revenue. China imported 800,000 barrels of Russian petroleum daily by sea last month, according to data from Refinitiv, a figure that does not include oil delivered via pipelines. The volume has soared by more than 40% from January. The number indicates that China is deliberately going after cheap Russian crude. India's marine imports of Russia's oil also spiked from zero in January to nearly 700,000 barrels a day in...