BSI and ZSI refer to two premier Indian government organizations dedicated to the study and documentation of the country's biodiversity:

• BSI (Botanical Survey of India) : Established in 1890, BSI is the apex research organization under the Ministry of Environment, Forest and Climate Change (MoEFCC). Its main objectives are exploring the plant resources of India, identifying plant species with economic value, conducting intensive floristic surveys, and maintaining authentic collections in herbaria. The headquarters of BSI is in Kolkata, West Bengal

• ZSI (Zoological Survey of India) : Founded on 1 July 1916, ZSI is also under the MoEFCC and is responsible for the survey, exploration, research, classification, and documentation of animal species across India. It originated from the Zoological Section of the Indian Museum established in 1875 and is headquartered in Kolkata. ZSI compiles faunal discoveries and maintains extensive collections of Indian wildlife

In summary, BSI focuses on botanical (plant) research and documentation, while ZSI focuses on zoological (animal) research and documentation in India. Both play crucial roles in expanding knowledge about India's rich biodiversity