India's capital is reeling from a double whammy of chikungunya and dengue - both viral diseases spread by the Aedes mosquito which is also responsible for Zika - with hospitals reporting dozens of cases of both diseases.
A clinic specially set up at the Hindu Rao Hospital, a government-run hospital in New Delhi, sees an average of more than 1,000 patients a day complaining of fever and joint pain.
A sharp jump in chikungunya cases is particularly worrying and is the worst outbreak in more than five years. According to the South Delhi Municipal Corporation, there were 64 chikungunya cases last year and that number has shot up to more than 2,600 so far this year.
Industry group Assocham fears a drop-off in tourist arrivals in the capital, the country's main entry point for foreign visitors.
"The rush in the outpatient department is overwhelming. I have never seen anything like this," said Dr Deepak Kumar Das, a doctor supervising vector-borne diseases. "There is some panic but there are more chikungunya cases than dengue this year.
"We can't do much... We give them paracetamol and fluid treatment, and if the parameters are ok, we send them home."
Number of chikungunya cases so far this year ; there were 64 cases last year.
Number of people who have contracted dengue so far this year.
The state government and municipal authorities have faced criticism for not taking adequate precautions, such as fumigation, to prevent a seasonal surge in the diseases.
In the crowded clinic, Ms Asha Devi, 46, and 13-year-old Jugal, too weak to stand or sit, share a bed. They are surrounded by their families as they wait for blood test results.
"We went to a private doctor and he said it might be chikungunya. We got scared and came to a government hospital for treatment," said Ms Asha's husband, Mr Sadhu Gupta.
New Delhi, with a population of 16 million people, sees an outbreak of dengue every year during the monsoon rains that start in July and continue through September. Chikungunya, the less fatal of the two diseases, is rarer.
So far this year, 1,373 people have contracted dengue, with 19 fatalities. Last year there were 3,791 confirmed dengue cases and 17 deaths.
Experts cite above-average rainfall and poor sanitation in some areas providing breeding grounds for mosquitoes as causes of the current outbreak.
Dr Ashok Puri, a consultant who lives in Greater Kailash, a posh locality in South Delhi, has had two bouts of chikungunya. In his block, he reckons almost every family has at least one member who has got the disease.
"I don't have any data but a lot of people around me are sick. They (the authorities) have been taken unaware, that's what it looks like. They never expected this," said Dr Puri, who heads the local residents' welfare association. "We have even stopped going for early morning walks because of the mosquitoes."
The Delhi High Court, after a complaint filed by a resident, has asked the federal and city governments to step up action, including house-to- house checks for stagnant water or waste that could breed mosquitoes.
The Delhi government, which had set up 355 fever clinics, has announced it will fumigate every Delhi street on alternate days and will clean up overflowing garbage bins.