Nairobi — Speaking at the launch of the Environmental Education and Awareness Initiative, Mr Michuki said manufacturers "will have to be stopped" if they do not stick to the ministry's directives.

The warning came a fortnight after five slaughterhouses in Dagoretti area were closed down for failing to meet environmental standards. One has since been re-opened after complying with the new rules.

The National Environment Management Authority had issued three-month notices to all factory and business owners directing them to stop discharging effluent into the Nairobi River.

Unep executive director Achim Steiner also joined the anti-pollution crusade saying it was aimed at making rivers "arteries of optimism".

"The rich pollute the rivers upstream and this affects the poor downstream," Dr Steiner said.

On Tuesday, Mr Michuki reaffirmed the ministry's commitment to protect the environment from further pollution.

"This is not a light matter, nor is it politics as usual," he said.

But even as efforts to rid the city of pollution began in earnest, Mr Michuki noted the challenges of sustaining the efforts.

Green levy

He said a comprehensive plan had been put in place to ensure that all projects aimed at a cleaner environment were sustained.

The minister also said that the Green Levy on plastics would be implemented and the proceeds used to clean up the environment.

Mr Michuki said he would work with the Ministry of Forestry and Wildlife in developing guidelines to protect fragile ecosystems.