An analysis of funding received by the national parties showed that between 2004-05 and 2018-19, the national parties have collected Rs 11,234.12 crore from unknown sources.
The report was prepared by the think tank Association of Democratic Reforms (ADR), on the basis of Income Tax returns and donations statements filed with the Election Commission by the political parties.
Total income of seven national political parties, BJP, Congress, Trinamool Congress, CPI(M), NCP, CPI and BSP, in financial year 2018-19 was Rs 3749.37 crore, the report said.
While the total income of political parties from unknown sources was Rs 2512.98 crore, the share of income from Electoral Bonds was Rs 1960.68 crore.
According to the report, during 2018-19, BJP declared Rs 1612.04 crore as income from unknown sources, which is 64 per cent of the total income of national parties from unknown sources.
This income of BJP forms more than 1.5 times more the aggregate of income from unknown sources declared by the other five national parties, which was Rs 900.94 crore.
The Congress declared Rs 728.88 crore as income from unknown sources which is 29 per cent of the total income of national parties from unknown sources.
According to the donations reports, containing details of donations above Rs 20,000 of 2018-19, Rs 71.44 lakhs was given to the national parties by cash.
At present, political parties are not required to reveal the names of individuals or organisations giving less than Rs. 20,000 nor those who donated via Electoral Bonds.
As a result, the ADR pointed out, more than 67 per cent of the funds cannot be traced and are from 'unknown' sources.