This article singles out Russia and Ukraine, but a larger issue is CFC-23, a nasty greenhouse gas. It's a chemical byproduct which Chinese and Indian companies are deliberately producing in order to destroy, because the cause the credits for destroying the byproduct are worth five times the value of stuff they're nominally trying to make.
The article mentions this, but doesn't mention that CFC-23 fraud supplies HALF of all the carbon emissions credits sold on the European market.
The cheating problem is a big part of why I favor a straight up carbon tax rather than trying to get fancy with incentives and credits. Place a flat tax per ton CO2e on companies which generate or import fossil fuels or CFCs. They will pass this cost on to customers, making goods that require lots of fossil fuels cost more, so the market will determine which emissions reductions strategies are most cost-effective. You can return the tax money to the people via lower income or payroll taxes, use it to reduce the deficit, or use it to pay for green infrastructure, I don't care. One more element is needed to make this work: you need import tariffs on manufactured goods coming in from countries that don't have a comparable carbon tax. Otherwise countries that "offshore" their emissions will have an advantage.
In addition to being simpler and harder to cheat, this system is preferable from a "big gubmint is evil" perspective. Conservatives don't want a massive government bureaucracy inspecting every element of the supply chain, making sure the incentives are properly spent and the credits fairly earned, and neither do I. I just want to use their worst enemy, taxes, to make their best friend, capitalism, work to help the planet. Put a green thumb on Adam Smith's invisible hand.
I'm a free-market environmentalist. I say we need to stop hoping that greed will go away, or worse pretending it doesn't exist, and start using it as a tool.