Presumably that would mean a veto first by Gov. Eliot Spitzer.
Crain's reports: The city wants to strike provisions providing the tax break to the Atlantic Yards project in Brooklyn, removing low-income neighborhoods like Crown Heights and the South Bronx from the areas where developers must build on-site affordable housing and exempting some projects with heavy government assistance from rules lowering the income limits for affordable apartments.
Interestingly, unmentioned is the six-month extension of the current law, which provides a significant boost to developers in Manhattan. The "Atlantic Yards carve-out" may be the most blatant example of favoritism, but the six-month extension would likely provide more overall tax benefits to developers.
On the radio
For more on 421-a, from Brad Lander of the Pratt Institute for Community Development and Daniel Goldstein of Develop Don't Destroy Brooklyn, listen to their Monday night appearance on WBAI's Housing Notebook (about 34 minutes in), hosted by Scott Sommer.