It may be difficult to obtain kids' snow boots in Lucknow because of the city's mild environment, where snowfall occurs seldom. It's possible that local retailers don't always have specialist snow gear.
However, possibilities for insulated, waterproof, or all-weather boots appropriate for colder temperatures may be found by looking through retailers that sell outdoor goods or winter footwear. Look for well-known companies that are well-known for their cold-weather assortments; even if they aren't specifically advertised as snow boots, they may include options for children.