Present Perfect Contin. - britain has been developing policies;
Past Indefinite Passive - the south-west coast of wales was seriously affected by one of britian's largest oil pollution incidents in 1996;
a major clean-up operation was done;
Past Indefinite Tense - oil leaked into the sea.
Present Indefinite Tense - britian helps international organizations on environmental protection.
the government controls over waste, air pollution, litter, noise and water pollution.
the national rivers authority is responsiblefor the control of water pollution in england and wales.