India has a nuclear program supported by the United States to counter the Soviet power in its neighborhood,
India and US have a trade deal in 2005, but India's nuclear weapon is built on their own and US tried to bully India with sanctions when Indian government tested their nukes but they played smart and did the smiling Buddha (Pokhran test) without knowledge of other governments. That is also the reason Pakistan wanted to have a nuclear weapon as soon as possible and they built their own a couple of decades later.
The US and Canada made important contributions in the early stages (1950-1960) of India's nuclear weapons development. India was banned and isolated by the United States only after it used technology provided for civilian purposes to make military bombs (in 1974). Since then, they have been forced to develop their own nuclear technology from uranium mining to production, reprocessing and waste management...
Not to mention, although the 2005 India-US agreement did not directly support India's nuclear program, it did give them easy access to imported uranium. This reduces the pressure on uranium in the country, thus making their nuclear research and development easier.
To put it bluntly, they stole the technology and then made it their own, India does not have the resources to produce nuclear weapons on its own.