Predicting about national event is categorized under mundane astrology. Like individual horoscope, horoscope of nation is casted and events are predicted accordingly. There is slight change in method of predictions compared to individual horoscope. In individual horoscope much importance is given to natal or birth horoscope where as in mundane importance is given to progressed horoscope. In natal astrology less importance is given to Uranus Neptune and Pluto but in mundane  astrology this farther planets r considered a lot. Earthquake rainfall war minerals agaricultural industries defense law and order etc are predicted based on transit progressed horoscope.  Important event do occur based on rare combinations. Like Saturn and Jupiter both exalted simultaneously in chart of India last year , result a change in government rise in stock market, image of India getting better in world. Etc