both psychological level and technical level;
For instance,
1) some are touching 100 EMA, Dow 10000-10100, FTSE 5200, Nikkei 10000-10200, STI 2700;
2) some are touching 200 EMA, HSI 20000, SSE 3000;
if these round numbers could have some resonance effect, the recent dropping momentum may be slowed down for a while,, but even the assumption does happen, I would rather assume it is just a temporary technical rebound,,,