His family presumed that he had suffered a heart attack but after day-long tests, the doctors said that high pollution levels were the reason behind his problem.
Rai's silk shop is in Ardhali Bazaar which has recorded the highest AQI of 811 in the Top 10 most polluted cities of India in the past 24 hours.
Vasundhara in Ghaziabad had an AQI of 327 while Nehru Nagar in Kanpur ranked third with AQI at 314.
The Ardhali Bazaar, originally known as Orderly Bazaar during the British Rule, is one of the most congested localities in Varanasi just like all other localities.
The roads are narrow, the sewerage system is unable to cope with the growing population and construction, renovation activities continue non-stop here.
"We have grown up seeing clouds of dust and garbage littered all around. Power cuts are frequent and majority of the shop keepers have diesel generator sets that emit smoke.
"The roads are congested at all times of the day but people are used to the conditions now. However, of late, there are more and more people complaining of burning sensation in eyes, short breath and even persistent cough. There is not too much awareness about pollution but I guess things are getting worse now," said another shop owner Mohd Ishtiaq from the parliamentary constituency of Prime MInister Narendra Modi.
A physician, S.M.S Trivedi, who has a clinic in Ardhali Bazaar, admitted that the impact of increasing pollution levels was evident from the increase in number of patients in almost all medical facility.
"Most people attribute the problems to changing weather but it is actually pollution that is taking its toll. This is Prime Minister Narendra Modi's parliamentary constituency and before we get other facilities, we should be given fresh and clean air to breathe.
"Since air is not visible, the administration does not bother about it but the adverse impact of worsening pollution levels can cost one's life," he said.
Most people in Varanasi attribute the increasing pollution levels to frequent power cuts and increasing construction work in the city.
"Wherever construction activity is taking place, there is no effort to put up the sheets so that the construction material does not fly out with the winds. "Hawa ke saath balu aur mitti bhi har jagah milti hai (we get sand and dust along with air everywhere," said Avinash Prakash, a BHU student.
( With inputs from IANS )