ISI full form - Indian Standards Institute, ISI is the certificate scheme under BIS (Bureau of Indian Standards) which confirms that a product withstands the BIS standards which ensures safety.
ISI certificate allows you to use the standards mark, i.e., ISI Mark. Since 1955, the ISI mark is the standards compliance mark for industrial goods. This mark ensures that the product has abide by the Indian Standards which are laid by the Bureau of Indian Standards (national standards body in India which confirms that the product is secure and credible).
Under the ISI certificate, a total of 346+ products falls, which requires an ISI certificate mandatorily, without which the manufacturer won’t be able to manufacture and sell products in India.