Pakistani women carry wood they have collected to be used as fuel for cooking and heating, in Islamabad, Pakistan, Monday, February 23, 2015. Domestic consumers are facing difficulties with cooking and heating due to a shortage of natural gas. (Photo by B. K. Bangash/AP Photo)

An Afghan refugee youth uses a shovel to create a sewage path near his mud home in a slum on the outskirts of Islamabad, Pakistan, Saturday, February 21, 2015. (Photo by Muhammed Muheisen/AP Photo)

Pakistani woman Hira Bibi shepherds her herd in Lahore, Pakistan, Wednesday, April 1, 2015. (Photo by K. M. Chaudary/AP Photo)

A Pakistani laborer takes a bath at a polluted stream outside Islamabad, Pakistan, Wednesday, March 25, 2015. There is a scarcity of fresh drinking water in Pakistan among its population of around 180 millions. (Photo by B. K. Bangash/AP Photo)

In this Wednesday, March 18, 2015 photo, Pakistan's Mohammed Ayub, second left, tries to convince children from slums, in Islamabad, Pakistan, to study at his makeshift school at the city's park. Ayub has dedicated three decades of his life to teaching underprivileged children. Now about three-quarters of his roughly 170 students go to government-run schools but some to his classes afterward for extra tutoring. (Photo by B. K. Bangash/AP Photo)

A Pakistani laborer washes clothes at a polluted stream outside Islamabad, Pakistan, Wednesday, March 25, 2015. (Photo by B. K. Bangash/AP Photo)

A Pakistani man, displaced from a Pakistani tribal area due to fighting between security forces and militants, walks in the rain with his cow, in suburbs of Islamabad, Pakistan, Tuesday, February 24, 2015. (Photo by B. K. Bangash/AP Photo)

Pakistani girls gather during a rehearsal for the Pakistan Day celebrations in Quetta on March 22, 2015. (Photo by Banaras Khan/AFP Photo)

A Pakistani vendor waits in the rain for customers, in Islamabad, Pakistan, Tuesday, February 24, 2015. (Photo by B. K. Bangash/AP Photo)

An Afghan refugee boy walks back to his family's mud home on sthe lippery ground of a slum during rainfall on the outskirts of Islamabad, Pakistan, Friday, February 20, 2015. (Photo by Muhammed Muheisen/AP Photo)

A fisherman from India looks out of a train window, after his release with others from a prison, at Karachi's Cantonment railway station, February 15, 2015. According to local media, Pakistani authorities released 172 Indian fishermen who were detained for illegally venturing into Pakistani waters, as a good will gesture and part of cricket diplomacy on Sunday. (Photo by Akhtar Soomro/Reuters)

A fisherman from India sits in train while being photographed, after his release with others from a prison, at Karachi's Cantonment railway station, February 15, 2015. (Photo by Akhtar Soomro/Reuters)

A fisherman from India looks out from a train window, after his release with others from a prison, at Karachi's Cantonment railway station, February 15, 2015. (Photo by Akhtar Soomro/Reuters)

A girl carries a broken brick on her head while walks along a littered ground in Lahore's slum, February 16, 2015. (Photo by Mohsin Raza/Reuters)

An arts student paints a mural on a wall in Lahore, February 16, 2015. (Photo by Mohsin Raza/Reuters)

A boy pushes another on a bicycle as they play along a littered ground in Lahore's slum, February 16, 2015. (Photo by Mohsin Raza/Reuters)

A woman and a girl walk on a muddy lane on their way home in a slum on the outskirts of Islamabad February 16, 2015. (Photo by Faisal Mahmood/Reuters)

Najeeb, 70, waits for customers while selling “bakarkhani”, a traditional snack, at his push cart along a road in Karachi February 16, 2015. (Photo by Akhtar Soomro/Reuters)

A woman, who lives with her family along a sidewalk, cooks near their makeshift home in Karachi February 16, 2015. (Photo by Akhtar Soomro/Reuters)

A woman mourns the death of her relative, who was killed in an explosion outside police headquarters, at hospital in Lahore, February 17, 2015. A Taliban suicide bomber on Tuesday killed six people and himself in a brazen attack on police headquarters in Pakistan's eastern city of Lahore, in what militants called a revenge bid for the recent hangings of colleagues. (Photo by Mani Rana/Reuters)

A woman is reflected in mirrors, decorated with sea shells and put up for sale, as she walks along Karachi's Clifton beach February 18, 2015. (Photo by Athar Hussain/Reuters)

A labourer pushes his wheelbarrow at a clay pots workshop on the outskirts of Karachi February 19, 2015. (Photo by Athar Hussain/Reuters)

A labourer arranges clay pots for drying at a small traditional factory on the outskirts of Karachi February 19, 2015. (Photo by Athar Hussain/Reuters)

A potter works on a clay pot at a small traditional factory on the outskirts of Karachi February 19, 2015. (Photo by Athar Hussain/Reuters)

Afghan youths sit on the roof of a car as they pass a picture of Afghan President Ashraf Ghani on a street in Kabul February 19, 2015. Senior Pakistani army and diplomatic officials said on Thursday the Afghan Taliban have signaled through the Pakistani military that they are willing to open peace talks, which could begin later in the day. (Photo by Omar Sobhani/Reuters)

People receive food from a charity, outside the Data Darbar Sufi shrine in Lahore February 19, 2015. (Photo by Mohsin Raza/Reuters)

Children play on a trampoline in open ground during dusk in Karachi's slum February 19, 2015. (Photo by Akhtar Soomro/Reuters)

Laundrymen fold a dry sheet of fabric after washing it along a street near the slum area in Karachi February 19, 2015. (Photo by Akhtar Soomro/Reuters)

A boy carries a sack of wheat husk while going back to his home in a slum on the outskirts of Islamabad February 20, 2015. (Photo by Faisal Mahmood/Reuters)

A girl carries her laundry after washing it in a polluted stream in a slum on the outskirts of Islamabad February 20, 2015. (Photo by Faisal Mahmood/Reuters)

A boy washes his feet in a polluted stream in a slum on the outskirts of Islamabad February 20, 2015. (Photo by Faisal Mahmood/Reuters)

A girl runs barefoot on cows dung at a slum on outskirts of Lahore March 11, 2015. (Photo by Mohsin Raza/Reuters)

A woman dyes her husband's beard at a slum in Islamabad March 12, 2015. (Photo by Zohra Bensemra/Reuters)

A woman talks on a mobile phone while sitting with her husband in her kitchen at a slum in Islamabad March 12, 2015. (Photo by Zohra Bensemra/Reuters)

Teenagers chat beside an open sewer at a slum in Islamabad March 12, 2015. (Photo by Zohra Bensemra/Reuters)

A boy carries a cooking pot on his head as he walks above an open sewer at a slum in Islamabad March 12, 2015. (Photo by Zohra Bensemra/Reuters)

A girl stands inside her house at a slum in Islamabad March 12, 2015. (Photo by Zohra Bensemra/Reuters)

Children study at a tuition centre at a slum in Islamabad March 12, 2015. (Photo by Zohra Bensemra/Reuters)

A girl comes climbs down a ladder at a slum in Islamabad March 12, 2015. (Photo by Zohra Bensemra/Reuters)

Ducks cross a wooden bridge over a stream of rain water and sewage in a slum that hosts Afghan refugees and internally displaced Pakistanis from tribal areas on the outskirts of Islamabad, Pakistan, Saturday, February 14, 2015. (Photo by Muhammed Muheisen/AP Photo)

Afghan refugees and internally displaced Pakistani schoolchildren attend a class at a makeshift school on the outskirts of Islamabad, Pakistan, Friday, February 20, 2015. (Photo by Muhammed Muheisen/AP Photo)

In this Friday, March 20, 2015 file photo, a displaced Pakistani girl, who fled from a Pakistani tribal area where security forces are fighting against militants, crosses a stream in suburbs of Islamabad, Pakistan. (Photo by B. K. Bangash/AP Photo)

Children play on a donkey cart belonging to an elderly Afghan refugee sleeping on a roadside on the outskirts of Islamabad, Pakistan, Wednesday, February 18, 2015. (Photo by Muhammed Muheisen/AP Photo)

An Afghan refugee girl carrying her younger brother walks back to her mud home in a slum on the outskirts of Islamabad, Pakistan, Saturday, February 14, 2015. (Photo by Muhammed Muheisen/AP Photo)

In this Thursday, March 12, 2015 photo, Pakistani children from slums study at a school set up by Mohammed Ayub, a 57-year-old government worker, at a park in Islamabad, Pakistan. Ayub has dedicated most of his life to teaching the less fortunate of this city. For three decades, children who might otherwise have gotten no education sat through his classes. (Photo by B. K. Bangash/AP Photo)

An Afghan refugee girl tends to her brother while sitting on the ground in front of their mud home in a slum on the outskirts of Islamabad, Pakistan, Sunday, February 22, 2015. (Photo by Muhammed Muheisen/AP Photo)

Internally displaced tribal people return to their villages cleared by the Pakistani army, in Bannu, Pakistan, Tuesday, March 31, 2015. Thousands of families are displaced from Pakistani tribal areas in North Waziristan along the Afghan border as the Pakistani army launched crackdown operations against Taliban and militants. (Photo by Ijaz Muhammad/AP Photo)

Pakistani children, who are displaced from tribal areas where security forces are currently fighting against militants, carry kites as they ride a cart in Islamabad's slums, Friday, March 27, 2015 in Pakistan. (Photo by B. K. Bangash/AP Photo)

Pakistani women pray at the shrine of famous saint Shah Chun Chirag in Rawalpindi, Pakistan, Thursday, April 2, 2015. People usually visit shrines on Thursday and Friday to get their wishes fulfilled. (Photo by B. K. Bangash/AP Photo)

Pakistani women carry wood they have collected to be used as fuel for cooking and heating, in Islamabad, Pakistan, Monday, February 23, 2015. Domestic consumers are facing difficulties with cooking and heating due to a shortage of natural gas. (Photo by B. K. Bangash/AP Photo)

Afghan refugee schoolgirls attend a class at a makeshift school on the outskirts of Islamabad, Pakistan, Friday, February 20, 2015. (Photo by Muhammed Muheisen/AP Photo)

An Afghan refugee girl holds an umbrella while she and two other children stand in the doorway of a mud home during rainfall on the outskirts of Islamabad, Pakistan, Friday, February 20, 2015. (Photo by Muhammed Muheisen/AP Photo)

People visit the Shrine of Bibi Jawindi, the great granddaughter of the saint Jahaniyan Jahangasht, who was known for her piety, in the historical town of Uch Sharif, Pakistan, 27 March 2015. Uch Sharif is a town believed to have been founded in 500 BCE, with some historians believing that Uch was there even before the advent of Bikramjit when Jains and Buddhists ruled over the area, and under Hindi rule during the time Alexander the Great's invasion. (Photo by Omer Saleem/EPA)