what is 貧苦懸殊 in english?

貧富懸殊 (Note : There is no 貧苦懸殊.)

If you mean 貧富懸殊, in English it can be:

Sentence:
The disparity between the rich and the poor is great.
The gap between the rich and poor is wide.

Phrase:
A wide wealth gap
A great wealth disparity

貧富懸殊
Wealth disparity between rich and poor is startling (or alarming)

Wealth gap between rich and poor has widened
~ found in the newspaper, The Standard (英文虎報)
http://www.thestandard.com.hk/news_detail.asp?pp_cat=11&art_id=47186&sid=14117720&con_type=1

如果要寫一句子, 長少少.意味貧富懸殊極端:

Hong Kong presents a picture of drastic poverty amid affluence, an extremity of contrast unknown in other industrial nations.

Disparity between the rich and the poor