National parties collected Rs 11,234 crore in donation from unknown sources from 2004-05 to 2018-19, according to election watchdog Association of Democratic Reforms (ADR).
For this analysis, the ADR said it considered the submission made before the Election Commission of India by seven national parties - BJP, Congress, Trinamool Congress, Communist Party of India (Marxist), Nationalist Congress Party, Bahujan Samaj Party and Communist Party of India (CPI).
The income from unknown sources refers to the funds declared in the Income Tax Returns without naming the source for donations below Rs 20,000.
Such unknown sources include donations via electoral bonds, sale of coupons, relief fund, miscellaneous income, voluntary contributions and contribution from meetings/morchas.
The BSP, however, declared that it did not receive any funds from voluntary contributions (above or below Rs 20,000) from the sale of coupons/electoral bonds or unknown sources of income.
"Between FY 2004-05 and 2018-19, the national parties have collected Rs 11,234.12 crore from unknown sources," the ADR said.
The details of donors of such voluntary contributions are not available in the public domain.
During 2018-19, the BJP declared Rs 1,612.04 crore as income from unknown sources which is 64 per cent of the total income of national parties from unknown sources (Rs 2,512.98 crore), the ADR said.
This is 1.5 times more than the aggregate income from unknown sources declared by the other five national parties (Rs 900.94 crore), it added.
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, the watchdog said.
"Combined income of Congress and NCP from sale of coupons between FY 2004-05 and 2018-19 stands at Rs 3,902.63 crore," it added.
Difference Of Nearly 6 Lakh Votes Polled, Counted In Lok Sabha Poll: Report 76% Of Regional Parties' Income Last Year Came From Unknown Sources: Report Donations Of National Parties During 2021-2022 Increased By 31.5%: Report Allu Arjun Summoned By Hyderabad Police For Questioning In Stampede Case Bengaluru Techie Loses Rs 11.8 Crore After "Digital Arrest" Pakistan May Get 40 5th-Gen Stealth Fighter Jets From China Within 2 Years "No One From BJP Can...": Chhattisgarh Chief Minister On Ambedkar Row 'Police Recruits From All Communities, Will Be Posted As Team': Biren Singh Shyam Benegal, Chronicler Of India's Times And Politics Track Latest News Live on NDTV.com and get news updates from India and around the world.