Is single transaction amount to business?

	assessee is in the business of construction. But in one year he has sold only one property.

The sell was from stock in trade?!!!

You said it yourself: "The assessee is in the business of construction". 

For him, the flats and apartments are stock-in-trade. Any sale of stock-in-trade is business receipts taxable under PGBP head of income.

The registration under ST or VAT is not the criteria for determining the head of taxability under INCOME Tax.

The definition of Business u/s 2(13) is very vast. In some instances, even 1 single transaction of sale can be regarded as business (concept of adventure in the nature of trade).

the problem here is how anyone can establish that  he is doing construction business without any indirect tax registration. He just bought, constructed and sold it. He is been there in that business since long time. any help would be appreciated.

He bought the land 3 months ago, constructed a building there on and sold it. His intention is to trade only. You are saying that service tax and vat registration has nothing to do with that. But how can he prove in case he got any notice. will there be any problem if we show it as a business income.