Shale Oil
Burden of EPA rules varies between states
Some regions will have to achieve steep reductions in carbon emissions while others will not, making the new standards vulnerable to legal challenge
US proposes biggest push for carbon cuts
Companies expected to challenge new limits in court after the Obama administration proposed a 30 per cent cut to emissions from 2005 levels
Putin rips up Sevastopol naval base lease
Russia cancels agreement that had limited the number of its troops at the Crimean base as Nato warns of military threat to Ukraine