A total of Rs 11,234 crore was donated to national political parties from unknown sources from 2004-05 to 2018-19, the Association of Democratic Reforms (ADR) said on Monday.

"Between FY 2004-05 and 2018-19, the national parties have collected Rs 11,234.12 crore from unknown sources," the ADR said.

The think tank came to the conclusion after taking into consideration the submissions made by seven national parties before the Election Commission of India (ECI). The parties include BJP, Congress, TMC, CPI(M), NCP, BSP, and CPI.

The income from unknown sources referes to the funds that have been declared by the parties in the Income Tax returns without naming the source for donations below Rs 20,000, according to AGR. Such donations are made through voluntary contributions and contribution from meetings, sale of coupons, relief fund, electoral bonds and miscellaneous income.

However, the Mayawati led-BSP informed the EC that it didn't receive any funds from voluntary contributions, from the sale of coupons or electoral bonds, and any unknown sources of income. On the other hand, an income of Rs 1,612.04 crore was declared by the BJP from unknown sources. This amount is around 64 per cent of the total income of national parties from unknown sources which is Rs 2,512.98 crore.

Meawhile, Congress received a total of Rs 728.88 crore as income from unknown sources.

It may be noted that the details of donors of such voluntary contributions aren't revealed publicly.