The footpaths are home to numerous families, and after dark, danger lurks. A Telegraph picture

It?s 11 pm, on a south Calcutta pavement. A mother, with a three-month-old infant in her lap, stirs a handi of rice and potatoes. She sets down her ladle to stuff some food into her five-year-old son Buddhadeb?s mouth.

As the cherubic child cheerily dances around, his sister sits patiently awaiting her meal. Mamoni Das, age 11, is on the verge of her very first flirtation. Two boys in her area have their eye on her and she has been spotted shyly chatting with them by the bus stop.

Tui ebar more jabi. Mamoni looks up, with a smile. A familiar voice; a friendly face. Telling her father he will die. He is just out of hospital, after being treated for liver failure, and tonight he is drunk, again.

Netai Mukherjee is on Night Watch. He is not a cop; he is a social worker. Every night at 10 pm, an ambulance and a Sumo set out from Panditiya Road for nightly rounds of the city with a team of three or four, scanning the streets and pavements for children in danger and families in need.

Every night, they pray they will find no one in distress. Most nights they do. Runaways, domestic violence, sexual molestation of young boys and girls, trafficking, accidents, medical emergencies?

The ?foot? is home to the Das family, as it is for thousands across Calcutta. In the bustle of day, these faceless folk blend with the crowd, shrouded by people, noise, light. As the sun goes down, the pavement gets its privacy. And with the hush stalks danger.

Mamoni?s family on SP Mukherjee Road is one of the first stops of the patrol this night. Pushpadi, another social worker, tries to convince the young mother who runs a tea stall that the girl is at increasing risk. Today, what is seemingly casual flirting could soon turn to abuse, and worse. There is an option: Mamoni will be taken off the street and put into the Hope Foundation home, where she will get a chance at a mainstream education and more importantly, safety.

The next stop is a few metres down the road, where a man in his 50s lives with his wife. He has a bad case of asthma. The patrol team, equipped with the medical basics, gives him an inhaler, carefully showing him how to use it. He is asked to visit the doctor at the clinic run by HIVE, supported by Hope, where Mukherjee works.

The emergency unit pulls up at a pavement near Southern Avenue, where a large family huddles after dinner. Kids play, mothers gossip, men lounge around, high on toddy or drugs. One intoxicated father screams at his son, commanding him to go to school, on the verge of violence. Apnara Kamal ke niye jaan (You take Kamal with you). Frustration and addiction fuel his attack on the confused child. ?His desires are conflicting. He wants his son to be something in life, but he can?t take the burden any more,? explains Mukherjee.

It?s 1 am, on a Sealdah railway station platform. Soni Kumari chews a piece of bubble gum. It is bedtime, but the 12-year-old is loath to spit it out. Her mother is getting Soni?s younger siblings ready for bed. She throws her arms around her midnight visitors, smile on her sweet face. She may like her guests, but she is in no mood to toe their line. They want to put her into school, but Soni is resisting. She may be a beggar, but she gets to stay with her family.

The magnitude of the misery sometimes gets the better of this team that takes it head-on. ?We think that some day, things will be okay? That they will fall into place. But that day will never come,? rues Mukherjee.

It?s 2 am, at the end of a hard patrol, and the sinister streets almost smirk their agreement.