Kathmandu, April 4 -- As winter gives way to summer, cases of fever, water-borne disease and respiratory illness are rising in major hospitals in the Kathmandu Valley. Also, air pollution has spiked in Kathmandu as the city has ranked as the world's most polluted consistently for the past few days.

Doctors say the exact cause of the upsurge in the cases of fever is yet to be established, but they attribute the rise in respiratory illnesses and waterborne diseases to increasing air pollution and contaminated food and water.

"Compared to the previous year, cases of respiratory illnesses have risen this year," said Dr Raju Pangeni, a pulmonary and critical care physician at HAMS Hospital. "Cases of fever and cough have also started rising....