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In parts of New York City, there are students who can barely read and write in English and have not been taught that dinosaurs once roamed Earth or that the Civil War occurred.

Some of them are in their last year of high school.

That is the claim made by a group of graduates from ultra-Orthodox Jewish private schools called yeshivas, and they say that startling situation has been commonplace for decades.

Over three years ago, Mayor Bill de Blasio’s administration opened an investigation into a lack of secular education at yeshivas that serve about 57,000 students in the city, but the probe essentially stalled almost as soon as it began. The reason, advocates say, is the city’s politicians, including the mayor, are fearful of angering the Orthodox Jewish community that represents a crucial voting bloc in major elections.

Then the state stepped in with the most significant action yet in the probe. MaryEllen Elia, the state education commissioner, released updated rules on Nov. 20 dictating how nonpublic schools like yeshivas are regulated and what students in those schools should learn, with consequences for schools that do not comply.