Russia declared a regional state of emergency on Saturday in Crimea, which it seized from Ukraine in 2014, as workers cleared tonnes of contaminated sand and earth on either side of the Kerch Strait after an oil spill in the Black Sea last month.Mikhail Razvozhaev, the Russia-installed governor of the city of Sevastopol, said new traces of minor pollution required urgent elimination and declared a state of emergency in the city of Sevastopol — giving authorities more power to take swift decisions such as ordering citizens to evacuate their homes.The Kerch Strait runs between the…