Is it allowed.?

In my opinion, there's no provision in income-tax act to claim alimony as expenses. so the entire salary income will be assessed in the hands of husband

Alimony, which is paid as a lump sum amount, is not taxable. As per the written law, lump sum alimony or maintenance is not classified as ‘income’ as defined under the Income Tax Act, 1961, and there is no specific provision that determines its taxability. As per taxation laws, this is considered as ‘capital receipt’.

However, if you receive the alimony as a monthly amount, it will be treated like a monthly salary or a ‘revenue receipt’, which is taxable. Also, the ex-spouse paying such alimony does not get a deduction against income. It is no doubt unfortunate that choosing to receive alimony every month as a safety net to meet expenses is subject to taxation.

However, this monthly alimony would not be liable for taxation if the ex-spouse pays a sum for certain expenses like house rent, school fees and household expenses.