It's cleaner than coal and oil. If you upgrade a coal plant to a gas plant, that's a step forward against climate change.

Yes, we'd be much better off with wind farms, solar plants, and nuclear reactors, but a step forward is a step forward.

Countries like Poland, running mostly on coal, would get cleaner air and contribute less to global warming if they were to upgrade their power plants to anything non-coal.

Replace them with nuclear generators and they'd also significantly reduce the amount of radiation people would be exposed to.

It's not that gas is that good, it's more that coal is that bad.

Clever use of the adjective “cleaner”. Try replacing it with “less dirty, but still pollutant and toxic” to see an alternative, correct version of what you have written.