In laws forcing daughter to apply for divorce. What action can I take?

In your situation, you have 2 possible situations and it all depends on what you want.

1. Filing a petition for restitution of conjugal rights under Section 9 of the Hindu Marriage Act. Section 9 has been reproduced below for better understanding: 

Restitution of conjugal rights.- When either the husband or the wife has, without reasonable excuse, withdrawn from the society of the other, the aggrieved party may apply, by petition to the district court, for restitution of conjugal rights and the court, on being satisfied of the truth of the statements made in such petition and that there is no legal ground why the application should not be granted, may decree restitution of conjugal rights accordingly.

Explanation- Where a question arises whether there has been reasonable excuse for withdrawal from the society, the burden of proving reasonable excuse shall be on the person who has withdrawn from the society. 

So in case, your daughter wants to stay with her husband, she can file a petition under Section 9.

2. Going for a divorce: Now if your daughter wants a divorce as well then she can file a petition for dissolution of marriage under Section 13(1)(ia) of the Hindu Marriage Act under the grounds of cruelty. As the treatment meted out to her by her husband and her in-laws amount to mental cruelty and therefore she can seek a divorce on this ground.

We strongly suggest that you should register a complaint for cruelty under Section 498A of the Indian Penal Code or for domestic Violence under the Protection of Women from Domestic Violence Act or both.

And the fact that you were married in Mathura and you are currently in Delhi will not be a problem as the women is allowed to register a complaint at her paternal place as well on compassionate grounds.

On separation, the wife has right to 'Stridhan' and all jointly-held investments where she has made some monetary contributions. Stridhan refers to the woman's personal wealth and encompasses all movable and immovable properties, gifts, and everything else received by her from her parents, relatives and even from her in-laws at the time of her marriage. It can include things like cash, gift-items, jewellery, car, furniture and more. She also has a right on all gifts received after her marriage, for instance those given to her on festivals and other functions.

It is beneficial if you have records of the same as, if the ex-husband refuses to part with items that come under 'Stridhan', you can back them up with relevant bills and receipts whenever needed. If the husband refuses, and it is proven beyond doubt that he is holding assets that legally belong to the wife, he is liable for criminal prosecution. Therefore you can easily claim the jewellery, certificates etc from your daughter's husband.

Your daughter is legally entitled to claim maintenance (alimony) as well from her husband under the Criminal Procedure Code and even under the Protection of Women from domestic Violence Act.