If we go by the facts then every day 2.5 Quintillion Bytes of Data is created in the world. This data also has the repetitive and erroneous records which we need to remove before mining it for insights in it. Inaccurate Data leads to wrong assumptions and analysis ultimately leading to failure of the project. Data Cleansing is the name of the process of correcting and eliminating (if required) inaccurate records from a particular database. The purpose of data cleansing is to detect so called Dirty Data to

Source: Best Offline Data Cleaning Tools