Before filing his nomination papers, PM Modi offered prayers at the Dashashwamedh Ghat on the banks of the Ganges and visited the Kal Bhairav temple in Varanasi.
The Kerala government has accused the Centre of interfering in the exercise of its "exclusive, autonomous and plenary powers" to regulate the state's finances by imposing a cap on borrowing.
Terming it a "scam," the plea filed by the NGOs has sought direction to the authorities to investigate the source of funding of "shell companies and loss-making companies” that made donations.