He was seen drinking water from the drain. Pest controllers frequently spray poisons into drains to prevent mosquito breeding.
He is at risk of being harmed by cat haters and abusers.
He is at risk of running across roads and knocked down by cars.
He is at risk of being rounded up by the town council's pest controller who will send him to be KILLED at the AVA.
So if you really love your cat, KEEP HIM or HER SAFE INDOOR!