Arrear claimed within the same financial year for which it is being claimed is approved by the DDO (Concerned AI of Schools) and he forwards payment advice to Treasury. It is credited within that same financial year. But if arrear is claimed for any previous financial year, the DDO cannot not approve it. The HM needs to submit it to the DI of Schools and the DIs will forward the bill to DSE. The bill is approved by DSE after verification. It takes times.