CHENNAI: In an apparent reference to China, Vietnam today asserted that "nobody" could prevent India's oil exploration efforts in its country, stating it was being undertaken in Hanoi 's exclusive territorial waters.He was responding to a query on China opposing exploration activities in South China Sea."We always welcome that (Indian investments). It is there already. The first gas exploration project was started in 1988 by ONGC (Oil and Natural Gas Corporation ). Now, it is exploring some more blocks in Vietnam," Ambassador of Vietnam to India Ton Sinh Thanh told reporters here.Stating that the projects were awarded in the territorial waters of Vietnam to India, he said, "India's exploration of oil and gas is in exclusively economic zone of Vietnam. So, nobody can prevent it".In October 2014, China had cautioned that it would firmly oppose any exploration activity in South China Sea if it undermines its sovereignty and interests, hours after India inked pact with Vietnam for exploration in two additional oil and gas blocks in the resource-rich area.On tourist arrivals from India to Vietnam, the Ambassador said it was increasing 100 per cent every year and was at 55,000 people in 2014."There is a 100 per cent increase. Last year 55,000 people from India visited Vietnam. This year, we expect another 100 per cent increase," he said.Speaking about the trade relations between the two countries, he said, "Vietnam trade with India stood at USD 5.5 billion last year. We export electronic products, sea food, rice, black pepper to India."On India's corporate presence, Thanh said there were 85 companies with investments of about USD one billion in Vietnam. They included major Indian automobile players like Bajaj Auto and Hinduja group flagship company Ashok Leyland On investments made by Vietnam companies in India, he said, "A few hundred Vietnamese communities are present in India."Thanh and senior officials were here to inaugurate the third VFS Visa Application Centre after setting up similar centres in Kolkata and Hyderabad.