How safe are the ISI marked helmets being enforced by the Indian lawkeepers?

Early afternoon on 2015-08-15, I (Deep Banerjee) was getting some minor repairs done in my car opposite the Mani Square Mall, EM Bypass, Kolkata. Suddenly, there were multiple loud screeching noise which drew my attention to the north (Ultadanga) bound flank of the high speed corridor.

There was a person lying right in the centre of the road or more towards the median divider where there are the pillars for the East - West Metro Railway corridor. His Bajaj Pulsar 150 motorcycle lay on top of him. Mechanics from adjoining automobile garages rushed to his aid. By the time I crossed the road, the tall & well built guy in his early thirties had been hauled to the roadside. His trouser below the right knee was torn and both his shoes were spoilt. He was visibly shocked and in pain.

A young man in a blue Maruti Alto 800 stopped his car about 15 mtrs ahead and also rushed to his aid while claiming that he himself was a doctor at R.G.Kar Medical College & Hospital. After a lot of efforts people could free the victim of his helmet. And that is when I realized that the person's head hit the road. The impact had actually cracked/ split the ISI marked helmet at various points.
Once the dark complexioned well built victim was freed of his Acron helmet, I noticed prominent bruise marks all over his right cheeks from below the eyes to the chin.

Some assistance from the doctor & pep-talks by the group of mechanics did wonders. The victim steadily managed to stand up on his own feet.
Thereafter, the doctor coaxed the victim to accompany him in his car to the nearest hospital or nursing home for some first-aid which he felt was necessary, while the neighbouring roadside garage guys assured the victim of the bike's safekeeping.

I shudder to think of the consequences if the man was not wearing a helmet at all or if he had been riding a more powerful/ heavier bike!

With more & more people riding faster and heavier bikes in India, the outdated ISI specifications related to technical and safety aspects must undergo a drastic revamp. No wonders, conscious riders are preferring DOT approved headgears and accessories.

In recent weeks superbike riders in Chennai & Mumbai have complained about police harassment for wearing expensive imported DOT helmets which have the capability to withstand greater shocks during accidents. And why? Because the imported helmets obviously do not carry ISI mark with outdated safety and technical specification standards.

Will the police realize their mistakes after seeing the pictures?