Is the following statement about urban living more accurate for the year 1900 or 2000?

Cities increase in size and suffer from overcrowding, contaminated water, filth, and disease

a. 2000

b. 1900

I'm 90% sure it's 2000 because urban areas now a days are overcrowed and cities have increased in size from the 1900's and the rest are pretty much both more for the 1900'spam than now but what I think it's more towards 2000's