The quarry cannot be dredged to clean it because during WWII, the Germans who occupied the island used it as an armaments dump and tonnes of unexploded ordnance remain.

BBC: Torrey Canyon seabed returns to normal after oil spill

The officials reply that Rome was not built in a day, and they cannot be expected to clean up Houston overnight: after all, it took 30 years to get that way.

ECONOMIST: The Lone Smog State

The question is where do we do that, and the priorities cannot be to get away from clean energy.

WHITEHOUSE: Press Briefing

As a consequence, the UN report has to steer clear of assets like clean air that cannot be directly owned, bought or sold.

ECONOMIST: A new report comes up with a better way to size up wealth

The property cannot be transferred to new ownership until the clean-up is complete.

ECONOMIST: Shutting military bases

Mr Putin cannot be expected to wipe the political slate clean at once.

ECONOMIST: What next, President Putin? | The

They have refused to make upgrades because costs cannot be passed on to drivers, and they will not cooperate with clean-up mandates until the Ministry of Finance picks up the tab.

FORBES: China Demands U.S. Taxpayers Clean Up Its Air

This includes the clean energy that creates green jobs and combats climate change, which cannot be denied.

WHITEHOUSE: President Obama Speaks to the Australian Parliament