The widespread of this crime can be reduced by imposing stricter penalties.

‘Widespread’ is an adjective, not a noun. Nouns used in this context might include  ‘incidence’, or indeed ‘spread’. These we might classify as ‘statistics nouns’, which are particularly useful in IELTS Task 1 writing.

‘Widespread’ as complement:

• This crime is widespread. However, its spread can be reduced by imposing stricter penalties.

‘Widespread’ as noun modifier:

• Widespread criminality can be reduced by imposing stricter penalties.

And if you’re interested in ‘spreading‘ and need a laugh, check out ‘manspreading‘!