Words can barely describe how bad air pollution was during the late nineteenth century in London, England. Coal was burned in excess, and the soot and sulfur dioxide that resulted is blamed for a shockingly increased mortality rate among infants. Indeed, it is estimated that about 50 percent of the children born in London at the time failed to live past the age of two. So much sunlight was blocked by coal dust that people suffered from lack of vitamin D, with the result being a rise in rickets. And, of course, respiratory ailments were rampant.