The Service Area Approach (SAA) is a rural development strategy that was implemented under the purview of the Lead Bank Scheme (LBS) in India. Here is a detailed explanation of the SAA and LBS:

Lead Bank Scheme (LBS):
- The LBS was introduced in 1969 by the Reserve Bank of India (RBI) to ensure that banking services reach all parts of the country.
- Under this scheme, each district of the country was assigned to one bank, which was responsible for coordinating the development activities of all the banks operating in that district.
- The lead bank was required to prepare an annual credit plan for the district, which would set targets for credit disbursement to different sectors of the economy.

Service Area Approach (SAA):
- The SAA was introduced in 1975 as a part of the LBS to ensure that banking services reach the rural poor and marginalized sections of the society.
- Under this approach, each bank was assigned a specific area, known as the service area, which would be its operational domain.
- The service area was chosen based on the concentration of rural poor and the bank's capacity to serve that area effectively.
- The lead bank was responsible for coordinating the development activities of all the banks operating in its service area and ensuring that banking services reach all the households in the area.
- The lead bank was also required to prepare a service area plan, which would set targets for credit disbursement to different sectors of the economy and identify the specific needs of the area.
- The SAA aimed to promote rural development by providing credit and other banking services to the rural poor, encouraging the adoption of modern technology and practices, and promoting entrepreneurship and self-employment.

In conclusion, the SAA was implemented under the purview of the LBS to promote rural development by ensuring that banking services reach the rural poor and marginalized sections of the society.