Indian officials declared an emergency in New Delhi over the weekend as the capital city entered its second week with air pollution levels as high as 30 times above World Health Organization guidelines, several news outlets reported.Construction sites have been closed, operations at a coal-fired power station halted, diesel generators stopped, and officials are preparing to reinstate traffic restrictions, all to reduce smog levels across the city, which have reached their highest levels in 20 years. Officials say field burning on nearby farmland and fireworks from the recent Diwali festival helped worsen the smog conditions.