The map below displays the top countries involved with Bitcoin mining. Data is displayed by their computational hash rate in percentages after China bans all cryptocurrency transaction and mining. Note that China was involved with more than 75% of the global hash rate before the ban and closing down of mining farms in March 2021. This caused many miners to flee to Kazakhstan and America to continue their endeavours. Below is a map displaying countries hashrate in Jan '22'. As you can see China still has mining operations even after the ban as miners would use VPN spoofing to keep authorities at bay.

The general worry is the kind of energy that these countries were using to produce the electricity required to power the computers were going to emit excessive amounts of Co2. Kazakhstan use the burning of fossil fuels like coal to power most of their bitcoin mining operation as it is cheaper alternative than renewable energy like hydro-electricity and wind energy. In the end of 2022 the Bitcoin mining industry's sustainable energy mix was estimated to be at 59.4%.