There were major changes following World War II. In the late 1950s and early 1960s, Harlem was the scene of a series of rent strikes by neighborhood tenants, led by local activist Jesse Gray, together with the Congress of Racial Equality, Harlem Youth Opportunities Unlimited (HARYOU), and other groups. These groups wanted the city to force landlords to improve the quality of housing by bringing them up to code, to take action against rats and roaches, to provide heat during the winter, and to keep prices in line with existing rent control regulations. The largest public works projects in Harlem in these years were public housing, with the largest concentration built in East Harlem. Typically, existing structures were torn down and replaced with city-designed and managed properties that would, in theory, present a safer and more pleasant environment than those available from private landlords. Ultimately, community objections halted the construction of new projects. From the mid-20th century, the low quality of education in Harlem has been a source of distress. In the 1960s, about 75% of Harlem students tested under grade levels in reading skills, and 80% tested under grade level in math. In 1964, residents of Harlem staged two school boycotts to call attention to the problem. In central Harlem, 92% of students stayed home. In the post-World War II era, Harlem ceased to be home to a majority of the city's black people, but it remained the cultural and political capital of black New York, and possibly black America.