That is beyond despicable. Those people should be barred from entry to prevent them from doing this. Unfortunately, with the current state of Nepal, I doubt they're capable of effective immigration control. Even so, these monsters would find prey among the vulnerable women there.
The problem is that the local politicians are also corrupt. They get commissions from these traffickers. Also, Indian citizens are allowed to enter Nepal without a visa. The government can't change this, because many hundreds of thousands of Nepalese workers eke out a living in India.