What could be causing bad breath in a two-year-old recently?

A 2-year-old child's recent bad breath may be due to poor oral hygiene, such as infrequent tooth brushing, leading to a buildup of dental plaque and soft debris on the tooth surfaces. This can trigger metabolic activity by oral microorganisms, causing odor. It could also result from cavities in the mouth where food becomes trapped and, if not cleaned regularly, is broken down by bacteria, producing a distinctive smell. Additionally, improper diet causing indigestion may also lead to bad breath in a 2-year-old child.