Currently here in the real world in this country, that just doesn't apply. Maybe in the future, but today your "clean" electricity is being generated by burning very dirty fossil fuels. Put your thinking cap on' I'm sure you will get it.
Not at the compressor, trace the line back to the pollution puffing fossil fuel burning power plant, and even someone as thick as you can see that it indeed does pollute, Christ!
You do in this conversation.
You stated "to refill the tank using electric compressors and it does not pollute." You were WRONG!
If either of us had the answer to that question we would be wealthy beyond belief. BUT neither you nor I can answer that question.
Burning fossil fuels in your internal combustion engine or burning them in the Fuel-fired electric power plants just moves where the pollution is produced, It does not eliminate it...
Untill there is a MAJOR change in how electricity is generated in this country, Fuel-fired electric power plants will continue to constitute the largest source of air pollution in the US.
Electricity today IS NOT CLEAN.