A federal judge has pushed back the deadline to April 21 for Volkswagen and regulators in the United States to come to an agreement on a fix for the German automaker's diesel cars.

Previously, the deadline was set for March 24 for VW to figure out how it will modify 600,000 cars sold in the U.S. that emit more nitrous oxide (NOx) from their tailpipes than what regulations allow. 

VW has to reach an agreement that will please both the Environmental Protection Agency and the California Air Resources Board, both of whom supported the automaker's request for an extension.

Rumors indicate that VW is aiming to reach an agreement that would allow some of its polluting vehicles to remain on the road since they may not be able to be fitted with a urea injection system that would put their emissions in line with federal guidelines.

Among the issues under debate is whether VW will have to compensate diesel buyers or if the automaker will be forced to buy back cars it sold. 

The scandal covers a wide variety of cars sold under the VW, Audi, and Porsche nameplates and has rocked the German automaker's operations worldwide. Earlier this month, VW's American market chief Michael Horn stepped down after more than 25 years with the company.

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