A Primary Agricultural Credit Society (PACS) is described by its own name: it is the basic, smallest co-operative credit institution in India, operating at the grassroots level, typically at the gram panchayat or village level. The Ministry of Cooperation puts the count at 1,01,718 societies with 13 crore members, which makes PACS by far the most numerous type of co-operative credit body mentioned anywhere on this site. The Ministry describes them as "the grass root level arms of the short-term co-operative credit structure" and as the final link between rural borrowers and "the Scheduled Commercial Banks, and the RBI/NABARD".
PACS exist primarily to serve agricultural credit needs in rural India, which sets them apart from the institutions most associated with pigmy or daily-deposit collection: urban co-operative banks, district central co-operative banks, patpedhis, Souharda co-operatives and Nidhi companies, all of which Pigmity found actively advertising a daily-collection deposit product. In researching this site, we looked specifically for PACS offering a branded pigmy or daily-deposit scheme and found none. That is an absence of evidence, not proof that no PACS anywhere runs one, and readers should treat it as unresolved rather than settled.
Like other credit co-operatives, a PACS is registered and governed under state co-operative law rather than licensed as a bank by the Reserve Bank of India, so the same caution that applies to a patpedhi applies here: deposit insurance and RBI's doorstep-banking protections are built for banks, and a PACS is a society, not a bank. If your account is at a PACS, establishing whether it is also licensed as a bank, rather than assuming from the passbook, is the question worth asking first.