MOSCOW — Russia fought a deadly battle Tuesday to prevent wildfires from engulfing key nuclear sites as alarm mounted over the impact on health of a toxic smoke cloud shrouded over Moscow. After almost two weeks of fires that have claimed over 50 lives and even part destroyed a military storage site, the authorities said they were making progress in fighting fires that still covered 174,035 hectares of land "A positive dynamic in liquidating the wildfires continues to be observed," said the head of the emergencies ministry's crisis unit, Vladimir Stepanov. The emergencies ministry said that over the last 24...