If there is no increase in volume during each price decline, it indicates a situation of "decline without volume". In a bearish market, the correlation between volume and price fluctuations can be ignored, which is also why the author prefers to trade in bearish markets.
Of course, where there is "decline without volume", there will also be "rise without volume". However, the frequency of "decline without volume" is significantly greater than that of "rise without volume", and the persistence of "decline without volume" is better than that of "rise without volume".