economical

"Walking is the most economical and environment-friendly way to navigate one's city and it's high time our leaders paid as much attention to walking infrastructure as they do to public transport," Mr Mhatre says.

Water flows with gravity in the aqueduct, making the supplies more economical than the city’s other imported sources, which require energy-intensive pumping.

Drilling for oil out at sea has become expensive compared with far more economical alternatives such as the fracking fields in the Permian Basin, which straddled Texas and New Mexico.

"It makes no political, economical or environmental sense whatsoever," said Paul Morozzo, Greenpeace's UK’s senior transport campaigner.

“These cars that have been damaged in the US, most of the time it does not make economical sense to rebuild them in the US,” says Mr Gulashvili.