Answer: Most likely the industrial revolution.
Explanation: The use of machines in production became more and more prevalent, eventually many factories were built in cities which caused pollution therefore making the air gross.
<span>Transcript of Positive and Negative Effects of the Industrial Revolution.
Working in a factory was not something people wanted to do. Pollution,
unsafe, dirty, long working hours, never any breaks. All of the coal
that was used for power became smoke after use.</span>
The British<span> government appointed consuls to some islands, but </span>their<span> powers to maintain order were limited and, except for the visits of warships, unenforceable.</span>
The second began to decline by 1870 membership rose rapidly among Baptist and Methodist conversations it enrolled millions of new members and led to the formation of new documentations
