Hi anujmenta nice work!
I also use Google Colab.
If I do not have to many images in my dataset of images, I prune them by hand, before I start training, this often helps make the model more accurate.
However your model appears to be working well!
A wonderful person called muellerzr has created a widget which apparently works on Google Colab, which may help now or in the future PR: New Widget! Class Confusion - With Google Colab Support!.
Have a fun day!
mrfabulous1 