Hello,
You are not required to show such a difference amount between the market value and sale deed value as your income from other sources.
The applicable section is 56(2)(x), which says that if any person receives an immovable property for a consideration which is less than stamp duty value of the property and such excess is more than the amount of fifty thousand rupees and the amount equal to five percent of the consideration then stamp duty value of such property as exceeds such consideration shall be taxable as income in the hands of buyer and chargeable under the head Income from Other Sources.
So you just need to make sure that the sale deed/sale agreement value of the property is either equal to or more than the stamp duty value of the property.
I hope that this answer satisfies your requirements.
Regards,
CA Hunny Badlani