Theory:

     “It’s too early, they’ve only eaten tiffin. If you’re still hungry, you’ll have to wait for them to finish lunch. You can wait if you want. I have to work, I’m going.” She picked up a couple of bottles from the heap and threw it into her sack. Then she walked off.

     Velu panicked. He realised that if the girl left him, he had no idea where he was and what to do. It was better to stick to her, she seemed to know her way around He ran after her again.
 
     “Aiy!” he called. He did not even know the girl’s name. “Aiy, what is your name?” he asked hurrying behind her.
 
     She stopped and turned around. “Oho! So you’ve been following me around without even knowing my name  Jaya”.
 
     “I’m not following you.”

     “What then? Who got you food?”

     “Can I come with you? Where are you going?”

     “Come if you want. This bag is full, I have to go home to get another one.”
Explanation:
 
After eating banana and Vada from the garbage, Velu felt hungry again. The girl told him if he felt hungry again, he can wait near the bin. The people would finish their lunch and they will throw the remaining in the bin. The girl had to move out to do her work again. So, she collected a couple of bottles from the pile of trash and put them into her sack and left the place.
 
shutterstock_1133596118.jpg
Plastics and glass in a pile of trash
 
Velu got scared, as he knew that he had no place to go if the girl left him. He did not know anyone in the city. So, Velu thought of sticking with her rather than roaming alone in this busy city. So he ran after her.

Velu used to call the girl "Aiy!" because he never asked her name before. Velu asked the girl, "Aiy, what is your name?" Suddenly, the girl stopped and looked back at Velu. Finally, she introduced herself as Jaya and he had been following her for a long time without knowing her name. Velu adamantly said he was not following her. Immediately Jaya questioned him, "What then? Who got you food?". Velu stood quiet for a couple of moments and asked her to take him along with her. Jaya said to him, "Come if you want" and she said her bag was too heavy to carry, so she wanted to return home to take a new bag.
 
Meanings of the difficult words:
 
S.No
Words
Meanings
1
TiffinA snack or light meal
2
PanickedFeel or cause to feel fear
3
TrashWaste material; refuse
4
AdamantlyIn a way that suggests one will not be persuaded to change one's mind; firmly and resolutely
5
Roaming Moving about aimlessly or unsystematically, especially over a wide area
Reference:
National Council of Educational Research and Training (2008). It so happened. Children at work- Gita Wolf, Anushka Ravishankar and Orijit Sen (pp. 7-16). Published at the Publication Division by the Secretary, National Council of Educational Research and Training, Sri Aurobindo Marg, New Delhi.