Midtown apartment project is ‘mining’ its air rights

City air rights are so valuable that they can even be “mined” like cryptocurrencies and then sold.

That’s what is going on at 42 W. 33rd St., a multifamily project with 223 apartments, of which 45 are affordable. Those units generated the 106,000 square feet of bonus square footage that will be ready to be planted elsewhere this spring.

Known as “inclusionary air rights,” the transferable development rights are likely to be sold in several tranches, said Brian Ezratty of Eastern Consolidated, who is marketing the thin air.

City rules allow them to land anywhere within its Community Board 5, which runs generally from 14th to 59th streets between Sixth and Eighth avenues. But it can also be sold within a half mile of the site, adding a huge swath of Midtown South to the mix.

The asking price is $375 per square foot.

Unfortunately, those air rights can’t hop over to 270 Park Ave., where JPMorgan Chase is already negotiating with the owners of the Grand Central Terminal air rights and others in the Midtown East rezoning area to buy 700,000 square feet — but at a price closer to $300 per square foot.

The financial giant wants to demolish its headquarters and build a newer, technologically upgraded and taller tower if it can fend off preservationists who are again calling for the former Union Carbide building to be landmarked and left as a museum piece so one day, the stagnant city could say, “We coulda been a contender.”