In 2019, the World Health Organization reported that India had 13 of the world's 20 most polluted cities. Although emission standards for diesel engines and generator sets was set in 2004, as recently as 2014 these standards were modified to be more stringent in an attempt to address the continued high levels of air pollution. Following these changes, the India Supreme Court began cracking down on Delhi generator pollution and frequently puts in place emergency orders to address dangerous levels of pollution.