Which period in India is known as Plan Holiday?

Due to the severe economic distress caused by the Sino-Indian War ($1962$), the Indo-Pakistani War ($1965$), high inflation, and catastrophic droughts that crippled agricultural production, the Indian government failed to implement the Fourth Five-Year Plan on time.
Instead, the period between **$1966\text{–}1969$ was declared as a "Plan Holiday"**, during which three ad-hoc annual plans were carried out.