A new front in the decades-long rivalry between India and Pakistan has emerged: which country is more responsible for the choking air pollution that straddles their shared, hostile border.

As residents of Lahore, Pakistan’s second-largest city, complained of shortness of breath, stinging eyes and nausea from thick, acrid smog that they compare to living in the smoke of a camp fire, the country’s minister of state for climate change smelled a conspiracy.

“Misinformation is being spread about Lahore air quality,” the minister, Zartaj Gul Wazir wrote on Twitter, before going on to blame India for the majority of the air pollution afflicting Pakistan. “It is nowhere as bad as being asserted by vested elements.”

The term “vested elements” is code for Pakistan’s enemies, India chief among them.

On many winter days, Lahore competes with India’s capital, Delhi, for the unflattering distinction of the world’s most polluted city. But while Delhi has slowly woken up to the danger of its hazardous air quality and put in place some — although not enough — government action to tackle it, Lahore has been much slower to respond, let alone recognize the problem.