"Whenever the government felt the air power element of the defence forces is likely to be in a disadvantageous position, it has gone in for emergency purchases of the aircraft under the umbrella of the inter-governmental agreement," Dhanoa said, addressing a seminar on IAF's force restructuring.
"The history is that the government had undertaken emergency purchase of fighter aircraft on several occasions in the past," he said.
The previous UPA government was negotiating a deal with French aerospace giant Dassault Aviation, the makers of the Rafale, for procuring 126 Medium Multi-Role Combat Aircraft (MMRCA). However the deal could not be sealed.
"By providing the Rafale and S-400, the government is strengthening the IAF to counter the shortfalls of our depleting numbers," he said.
The government is also procuring a batch of S-400 air defence missile systems from Russia.
The Modi government inked a government-to-government deal with France for the purchase of 36 Rafale jets at a cost of Rs 580 billion on September 23, 2016. The delivery of the aircraft will start from September 2019.
The Congress has been alleging massive irregularities in the deal and has attacked the government for procuring just 36 jets when the Air Force required 126.
Justifying the decision to go for only two Rafale squadrons, Dhanoa said India procured two squadrons of MiG 23 MF jets after Pakistan received the first lot of F-16 aircraft in 1983.
In 1985, he said two squadrons of Mirage 2000 were procured from France, and later two squadrons of MiG 29 were purchased from the then Soviet Union
"All this procurement was under the umbrella of the inter-governmental agreement (IGA)," he said.
He added that acquisitions under IGA are "faster" and the quickest means of achieving operational capability of the IAF.
The IAF chief said the force currently has 31 squadrons of fighter jets against the sanctioned strength of 42 squadrons.
"Even when we do have 42 squadrons, we will be below the combined numbers of two of our regional adversaries," he said, referring to China and Pakistan.