The Congress on Friday alleged that Gautam Adani's elder brother Vinod Adani was operating shell companies in "collusion with Chinese nationals" and asked whether the government should facilitate or investigate the group.
Posing a set of three questions to Prime Minister Narendra Modi as part of the party's "Hum Adani ke Hain Kaun" series, Congress general secretary Jairam Ramesh said the focus of Friday's posers was on the "disturbing Chinese connections" of a business group that has control of critical Indian infrastructure such as ports and airports.
The Congress's slew of allegations has continued weeks after Adani Group stocks had taken a beating on the bourses after US-based short seller Hindenburg Research made a litany of allegations, including fraudulent transactions and share-price manipulation.
The Gautam Adani-led group has dismissed the charges as lies, saying it complies with all laws and disclosure requirements.
In his statement addressed to the prime minister, Ramesh alleged that the Adani Group has a "longstanding" relationship with China.
"A Chinese national, Chang Chung-Ling (aka Lingo-Chang) has been a director in several Adani Group companies along with Vinod Adani and has also made an appearance in the Panama Papers," Ramesh claimed.
In December 2017, South Korea seized the Panama-registered oil tanker Koti for transferring petroleum products to a North Korean tanker in violation of UN sanctions, he said.
"It emerged that the Koti, which South Korea subsequently scrapped, was owned by Chang Chung-Ling's sons Chien-Ting Chang and Chien-Huan Chang. The Koti and the Koti Corporation are both on UN and US sanction lists," Ramesh said.
"There are deeper links with the Adani Group: Chien-Ting Chang is also known to be an owner of PMC Projects that helped construct Mundra and other Adani Group ports," he alleged.
What is Chang Chung-Ling's exact relationship with the Adani family, Ramesh asked.
"What influence do the governments of China and North Korea have over a group that controls strategic Indian assets and has a close relationship with India's Prime Minister?" Ramesh said in his statement which was part of a sub-series on the allegations against Adani -- "Dikh Raha Hai Vinod".
"Are you recklessly endangering the security of critical Indian assets by your dependence on a business group that is vulnerable to being influenced by China and North Korea," Ramesh asked the prime minister.
Why are there so many "murky connections" between the Adani Group and Chinese nationals engaging in illegal activity, he asked. What is their relationship with Vinod and Gautam Adani, he questioned.
"Only a JPC (joint parliamentary committee probe) can unravel the full political and financial dimensions of the PM-linked Adani Maha Mega Scam. No expert can or will," Ramesh said in a tweet.
The Supreme Court on Thursday ordered setting up of a six-member committee headed by former apex court judge Justice A M Sapre to investigate the recent Adani Group shares crash triggered by the Hindenburg Research's fraud allegations and other regulatory aspects related to stock markets.
Ramesh also claimed, "The Adani Group has repeatedly described Vinod Adani in filings as an NRI with Cyprus citizenship."
"Yet Dubai property records reportedly show that Vinod Adani holds an Indian passport expiring in 2026," he said.
Given that India does not have dual citizenship, how is it possible for him to have an Indian passport, the Congress leader said.
"Should the government facilitate or investigate a person accused of money-laundering and operating shell companies in collusion with Chinese nationals," Ramesh asked.