He graph shows air pollution in the city of London over time. A graph titled Air Pollution in London has year on the x-axis and particles (micrograms per cubic meter) on the y-axis. At 1700 the value is around 260; 1750, 360; 1800, 390; 1850, 580; 1875, 610; 1915, 380; 1950, 150; 2016, 20.

When did air pollution reach its highest point in London?

around 1825
around 1850
around 1875
around 1900

Where did the term “iron curtain” originate? the warsaw pact used the term iron curtain as a code word for communism. in a 1946 speech, british prime minister winston churchill said an iron curtain had fallen across the continent of europe. while visiting western europe in 1946, u.s. president harry truman commented that the mountains there looked like iron curtains. russian general secretary joseph stalin instructed citizens of eastern europe to hang iron curtains over their windows to protect themselves from stray bullets.