Why did this happen?
Pakistan is a poor country. Families with few viable means to cope with rising poverty and inflation often find that their women's sexuality is a valuable asset. Women are bartered for money, swara in NWFP and vani in Punjab, mostly in rural Pakistan. Few courageous women resist. Their rebellion is crushed by threatening them to be incarcerated for "adultery" under Hudood ordinance. Women in Prison are a testimony of this in-justice.(Read actual stories of women)
Before Hudood ordinace adultery was a sin not a crime. Under Pakistan penal code only husband could bring charges of adultery against women. After Zia's Islamization "adultery" became a crime under hudood and after Musharraf WPB(2006) , it now can be tried under Pakistan Penal Code. (Click here)