NEW DELHI The CBI raided a television station linked to the government on Friday, as a widening investigation into a corruption scandal threatens the coalition and scares off investors.
Prime Minister Manmohan Singh is under growing pressure over his role in the illicit sale of mobile phone licences, although he has said he would not resign, blaming the debacle on his sacked telecommunications minister, who is now under arrest.
Here are details on some major recent scandals:
TELECOMS LICENCE ROW
India may have lost up to $39 billion in revenue when the telecoms ministry gave out lucrative licences and radio spectrum in 2007/08 at below-market prices, the state auditor has said.
Tycoons Anil Ambani, who controls India's No. 2 mobile phone operator Reliance Communications, and Prashant Ruia, who runs one of India's biggest business houses, Essar Group, have both been questioned this week about the telecoms case.
The Comptroller and Auditor General of India's (CAG) report in November also said rules were flouted when the licences were awarded, which led to many ineligible firms winning licences.
Telecoms minister Andimuthu Raja was sacked in November after the report was released. He was arrested this month on charges of misuse of ministerial office and criminal misconduct. Raja denies the charges.
This month, the Central Bureau of Investigation (CBI) arrested the managing director of India's DB Realty and vice chairman of Etisalat DB.
Etitsalat DB is a joint venture between DB Group, the parent of DB Realty, and Abu Dhabi's Etisalat. DB Group sold a 45 percent stake in Swan Telecom to Etisalat after the operator was granted a licence by Raja despite being ineligible. Since Swan Telecom has been renamed Etisalat DB.
The CAG report also said units of realtor Unitech (UNTE.BO) were given licences despite not having adequate capital. The units are now part of the India operations of Norway's Telenor.
All firms have denied wrongdoing, and said they complied with all rules when licences were given.
ANOTHER TELECOMS SCANDAL
India's space agency is being probed by the CAG for granting a private firm lucrative mobile Internet bandwidth in 2005 without a proper bidding process that reports say has cost the government up to 2 trillion rupees ($44 billion).
Reacting to criticism, the government on Friday cancelled the contract under which the Indian Space Research Organisation (ISRO) leased transponders on two of its satellites to private firm Devas Multimedia, which granted it access to S-band telecom spectrum, worth billions of dollars to communication providers.
Prime Minister Singh, who personally oversees India's space department, denied in early February any revenue had been lost.
S-band spectrum, while not currently in extensive use, is likely to become increasingly valuable in India's rapidly-growing mobile phone market, with its ability to provide wireless broadband and other mobile data services.
ISRO said it granted Devas improper access to a valuable resource in a flawed contract that undervalued the spectrum.
LOAN BRIBERY SCAM
Top officials of Indian banks, lenders and financial firms have been accused of taking bribes to grant corporate loans.
The CBI, India's federal investigative agency, arrested eight people in November, including the chief executive of LIC Housing Finance and senior officials at state-run Central Bank of India, Punjab National Bank and Bank of India.
The bribes were allegedly paid by private finance firm Money Matters Financial Services MONE.BO, which acted as a "mediator and facilitator" for the loan beneficiaries, the CBI said.
Three Money Matters executives, including the managing director, have been arrested for offering bribes.
Several leading Indian firms were named in court documents filed by the CBI, including wind turbine maker Suzlon Energy, infrastructure company HCC's Lavasa unit and real estate firm DB Realty. All three have denied any wrongdoing.
The sporting extravaganza last October, which cost up to $6 billion, was dogged by several cases of alleged corruption, including the purchase of equipment and issuing contracts. The anti-corruption watchdog has identified more than 16 projects with possible irregularities.
The allegations include manipulations of tenders for building stadiums and other games infrastructure, and inflating bills for equipment including treadmills and toilet paper.
Several bodies, including the anti-corruption watchdog, the state auditor, the CBI and a special committee set up by Prime Minister Singh, are probing the allegations. The CBI has also raided the homes and offices of the Games organisers, part of a probe into $21.7 million of misplaced funds.
Congress party politicians, bureaucrats and military officials have been accused of taking over a plush Mumbai apartment block intended for war widows.
After the story broke in local media the government sacked the powerful chief minister of western Maharashtra state, who is a member of the Congress party.
Following a CBI probe, the environment ministry ordered the demolition of the 31-storey building in January, citing the violation of environmental and land-use rules.
The Arabian Sea-facing block with 103 apartments is built in an upscale Mumbai district. Apartments were sold for as little as $130,000 each, while local media estimated their value at $1.8 million each.
(Compiled by Henry Foy, C.J. Kuncheria and Krittivas Mukherjee; Editing by Paul de Bendern and Sugita Katyal)