Question

how can you say that London became a crime city in 19th century

Answer 1

It led to deterioration of law and order  and hence worries for police
2) It led to deterioration in public morality which made Philanthropists very anxious 
3) Industrialists wanted a hard working and orderly labour force
To control the crime, police started counting of population of criminals,
watched their activities and investigated  their ways of life.

Answer 2

Héy Héllø.. Guys...

NamAsTe

Here is your answer... ✔✔

So, Thé ÃnSwer is.. : .... This article covers the 19th century history of London, during which it grew enormously to become a global city of immense importance, and the capital of the
British Empire, fed by immigrants from the colonies and refugees from various conflicts and famines. Railways connecting London to the rest of Britain, as well as the London Underground were built, as were roads, a modern sewer system and many famous landmarks.

#ThanKyou....

NamaSTe........ I hope It's Help!!...

@RamSharma..... (model)...