The bad air quality is not only affecting people and businesses, but is also making animals here sick.

Vets have been reporting an increase in the number of pets suffering from eye irritations and upper respiratory infections that they are attributing to the haze.

"There hasn't been an increase in the overall number of visits, but my colleagues and I have definitely seen more cases of pets suffering from environmental allergen-related problems such as increased tearing, eye infections, asthma and coughing," said Dr Angeline Yang, 28, of United Veterinary Clinic in Ang Mo Kio.

At The Animal Doctors veterinary clinic, also in Ang Mo Kio, Dr Cathy Chan, 35, has not been seeing any extra cases but believes this is because pet owners are being more vigilant about keeping their animals indoors, thus potentially reducing the number of cases.

"However, since the haze was at its worst only on Thursday, it may still be too early to tell, as the symptoms arise only several days later," she added.

Some pet-related events have also been cancelled because of the deteriorating air quality.

The Singapore alliance of the United States Dog Agility Association (USDAA), which organises canine agility trails here, has cancelled trials originally scheduled for today.

Animal shelters have put in place safety measures.

Staff at the Society for the Prevention of Cruelty to Animals (SPCA) have been closely monitoring its shelter animals for signs of possible haze-induced afflictions.

"The shelter's fans have all been powered on around the clock and water in the water bowls is more frequently replaced too," said SPCA executive director Corinne Fong.

"Dog walks have been minimised and the dogs will not be taken out for walks once the 24-hour PSI reading breaches the 200 mark," she added.

With the hazy conditions expected to persist, pet owners are keeping their critters indoors.

Marketing assistant Amy Lin, 26, said: "I usually take my dog out for a walk every day, but since

the haze has got bad, I've been taking him out only about twice a week.

"I feel bad but I don't want him to be outside for too long because it's bad for him."

•Additional reporting by Tiffany Fumiko Tay