Oil and gas exports have sustained Russia's finances throughout its war against Ukraine. But as the fourth anniversary of the full-scale invasion approaches, those cash flows have suddenly dwindled to lows not seen in years.

It's the result of new punitive measures from the U.S. and the European Union, U.S. President Donald Trump's tariff pressure against India, and a tightening crackdown on the fleet of sanctions-dodging tankers carrying Russian oil.