Government subsidy- tax treatment

A company has received a govt subsidy amounting to Rs 15,00,000 in the asst year 1983-84. it offered the amount to taxation in the same asst year. 

Now, the charge created in connection to the asset is vacated. will the charge thus vacated will be taxable even the initial amount was offered to tax.?

please validate. reference of case laws will be a welcome step.