Unfortunately there are lots of piles of waste in parts of Bangalore, and cows are often seen eating vegetable waste. Some of this waste is produced from the large farmers markets in Bangalore, but some cows eat through piles of waste that has been dumped by citizens illegally.
The biggest concern with cows is a car or motorcycle not seeing a cow in the road! Luckily, traffic in India moves very slowly because the streets are so busy, and drivers are used to going around a cow.
