Bitcoin mining is considered environmentally unfriendly because it uses fossil fuel energy. If crypto or bitcoin mining uses solar energy or water, surely the mining will be environmentally friendly. In my opinion, in addition to the proof of stake system, using a proof of work system like bitcoin is also not a problem as long as it uses environmentally friendly renewable energy.
In my opinion, if it is a matter of bitcoin mining that is ridiculous, the percentage of environmental pollution from bitcoin mining has never been found significantly more than the waste of companies that use coal, or exhaust fumes from motor vehicles.