A toddler died after slipping out of her mum's arms and tumbling three floors off an escalator at a busy shopping centre.Horrifying CCTV footage shows the stumble on the stairs and lose grip of the tot.The youngster cannons head-first off railing and plunges three floors to the ground floor.She was rushed to hospital where she was pronounced dead in Sri Ganganagar, north-west India.Shocked witnesses claim the couple were taking selfies after stepping on the escalator.It is said the wife lost her balance as she prepared for a selfie.