Some examples of major crisis:

• Separation from Malaysia

• Unemployment caused by British withdrawal

• Asian Financial Crisis

• SARS

• Great Financial Crisis

• Covid-19 Pandemic

This question is subjective and will likely rely on several heuristics to resolve:

• Did the economy / stock market react negatively in a significant way?

• Number of lives lost

• Financial cost

• Did the government use significant amount of resource to manage the crisis? For example, draw on reserve.

• Has the event stayed in media headline for several weeks / months?

• Is there a Wikipedia article about the event?

I will propose candidate resolution after the deadline and there will at least be a one-week deliberation period.