Ebbing in Context:
In the given context, the word ebbing means that the momentum of the movement is giving away, it is falling to pieces.
Ebbing comes from the word ebb. Ebb can mean the following:
1. The flowing back of the tide as the water returns to the sea ( opposed to flood, flow).
2. A flowing backward or away; decline or decay: the ebb of a once great nation.
3. A point of decline: His fortunes were at a low ebb.
From the above, we derive the meaning of ebbing: a gradual decline (in size or strength or power or number).
Three idioms based on the word ebb and in common usage are:
Ebb tide: the ebbing tide: They sailed on the ebb tide.
At a low ebb: In a poor or depressed state: She was at a low ebb after the operation.
On the ebb: Ebbing or getting less: His power is on the ebb.
The following is an extract from The Times Of India used for educational purposes: ‘The Arab world finds itself at a significant crossroads. While the wave of pro-democracy protests witnessed over the last six months has shaken up regimes from Bahrain to Syria, the Arab Spring has slowly turned into a sapping Arab Summer. With the initial momentum ebbing, confusion and uncertainty are setting in.’