Is data redundancy leads to data inconsistency?

yes. data redundancy is where there is duplication of data in a database. when this happens, anyone who has to make updates to a table in a database (that is, make changes to the database) will have to change that particular data that has been duplicated so many times in so many places. this creates a problem and it is not always going to be possible for a person to change everything correctly. this therefore leads to inconsistencies in the database. hope this helps.