Improve nowadays in organised purge (7)
I believe the answer is:
upgrade
'improve' is the definition.
(to upgrade is to improve or make better)
'nowadays in organised purge' is the wordplay.
'nowadays' becomes 'AD' (AD, Anno Domini, as opposed to BC, Before Christ).
'in' means one lot of letters goes inside another.
'organised' indicates anagramming the letters.
'purge' is an anagram of 'upgre'.
'ad' inserted inside 'upgre' is 'UPGRADE'.
(Other definitions for upgrade that I've seen before include "Raise to higher standard" , "Raise to higher rank, or improve equipment" , "promotion" , "Bonus for plane passenger" , "Higher-standard version" .)