BBC: The US Supreme Court has blocked a key government attempt to limit pollution from the country's power plants. In a 5-4 split, the court ruled that the Environmental Protection Agency failed to factor in the full financial cost to industry of the changes. The government introduced new rules to restrict emissions of toxins, including mercury, three years ago. But several US states and companies challenged the changes, and the issue now returns to the US Court of Appeals. The government has made...