GST, or Goods and Services Tax, is a value-added tax implemented in India since July 1, 2017, replacing various indirect taxes like VAT, excise duty, and service tax. There are four GST rates in India - 5%, 12%, 18%, and 28%, with some exemptions and special rates for specific goods and services. Registered businesses collect GST from customers and remit it to the government while claiming input tax credits. This tax is applicable to goods and services provided within the country, and it aims to streamline the taxation system and reduce cascading effects.