As part of a city improvement project to eliminate what was known as the “red-light district,” Allen Street was widened in 1932 from its original 50 feet to 138 feet. Tenements were removed on its eastern edge (Mendelsohn 2009, 154-155). There were about 600 people per acre that were displaced, mostly Jewish immigrants. The “cleaning up of the Lower East Side” continued in 1938 when Mayor LaGuardia’s administration banned peddlers from the streets and relocated them to indoor markets. There wasn’t room for everyone in the indoor markets, which put many immigrants out of work. The number of peddlers decreased from 15,000 to 1,200 by 1945 (Dans and Wasserman 2006, 160).

Demolition of a tenement on the Lower East Side. Source: Photograph by © Allan Tannenbaum. Available at the Lower East Side Tenement Museum.
To see how Allen Street changed over time, go to: http://maps.nypl.org/warper/maps/15574#Preview_Rectified_Map_tab. Use the transparency bar at the bottom of the page to see the differences between the historical map and the current one. Source: NYPL’s Map Division, Map Warper. The historical map is from Maps of the City of New York, Third Edition, by William Perris: 1857.
Other tenement demolition projects took place nearby on Eldridge, Hester, and Pitt Streets. They are easily seen in the G.W. Bromley and NYC Housing Authority maps below.

G.W. Bromley fire insurance map from 1934. Note the tenements between Eldridge and Allen Streets. Source: G.W. Bromley Atlas of the Borough of Manhattan: 1934-Present. Available at NYPL's Map Division.

G.W. Bromley fire insurance map from 1974. Note how the tenements no longer exist between Eldridge and Allen Streets. Source: G.W. Bromley Atlas of the Borough of Manhattan: 1934-Present. Available at NYPL's Map Division.
After the Immigration and Nationality Act of 1965 was passed, it reopened America’s door to Chinese immigrants. Also, the ending of the Vietnam War in 1975 prompted tens of thousands of immigrants from South Vietnam, Cambodia, and Laos to flee to America. Many of these immigrants settled on the Lower East Side (Cayton and Williams 2001, vol.2, 317). This caused shifts in ethnic groups and an increase in population in the area. To accommodate the needs of the new wave of Asian immigrants, M.S. 131 Dr. Sun Yat-Sen was created. This replaced J.H.S. 65, tenements, and businesses at 100 Hester Street.

This G.W. Bromley fire insurance map from 1974 shows the tenements and J.H.S. 65 before the demolition and reconstruction projects that occurred during the late 1970s and early 1980s. Source: G.W. Bromley Atlas of the Borough of Manhattan: 1934-Present.

Map from the NYC Housing Authority. This map shows the reconstruction of the school at 100 Hester Street (see the lower left hand corner of the map). It also shows a current view of the housing project at 45 Allen Street (with second entrance at 85 Eldridge Street). See the differences between this map and the G.W. Bromley fire insurance maps above. Source: New York City Housing Authority, http://www.nyc.gov/html/nycha/html/home/home.shtml.

G.W. Bromley fire insurance map of Pitt Street in 1934. Note the number of tenements here and compare this map to the NYC Housing Authority Map below. Source: G.W. Bromley Atlas of the Borough of Manhattan: 1934-Present. Available at NYPL's Map Division.