Malayappan,
I would not discount the possibility of Beijing's hand behind the ISI's handover of Rigi to Iran.
Consider what Vikram Sood says in his article:
The Chinese have already begun to move into Afghanistan with their commercial and resource interests as they see an opportunity to move closer to the Persian Gulf, given their steady relations with Iran. The Chinese would see themselves moving into empty spaces up to the Persian Gulf vacated by a retreating American empire without having fired a bullet or lost a man.
As a strategic ally, Iran is more important to Beijing than the Pakis in the long term. The Pakis have their uses, such as containing India and influencing a post US Taliban dispensation in Kabul; but they also play footsie with the Americans in a way that Teheran never will.
From Beijing's POV the last thing they want to see is a Russia-Iran-India axis re emerge against a future Taliban regime in Kabul. That would push Pakistan and it's proxy regime in Kabul closer to the US, limiting Chinese influence in both Afghanistan and Pakistan. So they want to be very careful to keep both Pakistan and Iran in the Beijing camp; covering all their bets in Afghanistan when the Americans leave. The long term interest of the Chinese, as Sood suggests, is projecting influence via Afghanistan all the way to Iran's gulf coast. A Teheran-Kabul-Urumqi pipeline would be a godsend for China, allowing them to secure an energy supply route overland that neither Indian nor American naval power could threaten.
To achieve this, in the short term at least, Beijing needs both the Pakis and Iranians to be in its corner. The Pakis to ensure that a stable China-friendly regime is installed in Kabul after the US leaves; and the Iranians to avoid queering the pitch for such a regime by allying with Russia and India as they did in the nineties. Hence they may have prevailed upon Pakistan to give Rigi to Teheran as a peace offering and a CBM that Pakistan would not allow itself to be used by the CIA to destabilize Iran.
The Pakis are hedging their moves that apparently collaborate with America (selectively arresting certain Talibs etc) by simultaneously going along with the Chinese program to build an Iran-Pak-China axis centered around mutual interests in post-US Afghanistan. They know the US wants nothing more than to be out of Afghanistan, and that when they depart they may no longer continue to be as generous with baksheesh. Also, the Pakis don't want to see an Iran-India-Russia axis emerge that could threaten their own candidate government in post-US Afghanistan.
Alliances are shifting. India under MMS has made the stupid mistake of repeatedly alienating the Iranians at America's behest; this will have contributed to the likelihood of Iran drifting toward a China-Pak combine to secure it's Afghan interests, rather than the India-Russia combine of the past. It is perhaps partially to hedge against this that the GOI has now begun to woo Saudi Arabia, engaged in a proxy war against Iran in Yemen. But as with all the hapless measures taken by those in South Block who have the unenviable job of cleaning up the mess in MMS' wake... I fear that whatever results were achieved there have been too little, too late.
). Thats what MKB seems to be suggesting.