Lucknow, Dec 16 (IANS): The mercury has started dropping all over Uttar Pradesh but more than the cold it is the fog and smog that is proving to be a major cause of trouble for the people who are prone to respiratory problems.

Hospitals in Lucknow, Kanpur, Prayagraj and Agra have already reported a surge in patients with respiratory problems.

"Though the cold wave has not yet set in -- in the true sense of the term, and minimum temperatures have hovered around 9 degrees Celsius; it is the smog that hangs heavy in the air and is causing problems for those with respiratory issues," said P.K. Tripathi, a pulmonary disease expert.

He said that this could enhance the problems of those who are in the Covid and post-Covid stage.

"The patients in these categories are extremely susceptible and should guard against exposure. Those with asthma should also refrain from moving out. Delhi has been very cold and it will take two to three days before central Uttar Pradesh starts begin to feel the chill," he explained.

S.S. Mathur, a private practitioner in Agra, said that dip in temperatures would cause more problems amid the Covid outbreak.

"The number of patients with breathing problems has almost doubled in my clinic during the past one week. This weather is all the more dangerous for those having an asthma history. Such people should confine themselves to their homes as far as possible," he said.

The dense fog that has been reported from western part of the state since the past three days, has already led to a number of road accidents due to poor visibility. There have been several accidents on the expressway and pile-ups too.

Chief Minister Yogi Adityanath has already directed all district officials to make arrangements for night shelters for the homeless and set up bonfires across the districts.