Is swimming good for babies? what about the pool water?

Yes: Swimming is hardly the term to use. Introducihng an infant to a swimming pool or the shallows of a lake or ocean in proper season and with complete parental control is great fun. All my children and grandchildren were introduced in this way and none ever feared the water. They all swim very well now.

Depends on reason: I find infants/toddlers/kids do well in the water and enjoy the process when used as a a fun activity. Parents need to understand that it must be closely supervised and kids warned never to go near water unless an adult is with them. Swimming "lessons" are a problem when uses as a "safety" measure in children. You can NEVER drown proof a kid,ever, with lessons and I don't suggest them before 4y.