The reason Ghaggar-Hakra no longer is believed to be Sarasvati is because it was monsoon-fed river and Rig Veda clearly mention that Sarasvati was Himalayas-fed river.
Also recent definitive study by Giosan et al in PNAS (Fluvial landscapes of the Harappan Civilization; 2012; June 26; 109 (26): e1688-94) which clearly demonstrated that the the much touted Ghaggar-Hakra was a monsoon-fed river, not the Vedic Sarasvati fed by the melting snows of high mountains.
Numerous speculations have advanced the idea that the Ghaggar-Hakra fluvial system, at times identified with the lost mythical river of Sarasvati (e.g., 4, 5, 7, 19), was a large glacierfed Himalayan river. Potential sources for this river include the Yamuna River, the Sutlej River, or both rivers. However, the lack of large-scale incision on the interfluve demonstrates that large, glacier-fed rivers did not flow across the Ghaggar-Hakra region during the Holocene. Existing chronologies (27, 28) and our own age on the bank of Sutlej (SI Text) identified deposits of Late Pleistocene age, indicating that the interfluve formed instead during the last glacial period. Provenance detection (32) suggests that the Yamuna may have contributed sediment to this region during the last glacial period, but switched to the Ganges basin before Harappan times."
Contrary to earlier assumptions that a large glacier-fed Himalayan river, identified by some with the mythical Sarasvati, watered the Harappan heartland on the interfluve between the Indus and Ganges basins, we show that only monsoonal-fed rivers were active there during the Holocene.
Fluvial Landscapes of the Harappan Civilization, Giosan et al, PNAS Early Edition, May 2012
In other words, while the Yamuna could have fed the Ghaggar-Hakra in the pleistocene period (pre-10000 BC), it could not have fed the Ghaggar-Hakra in the holocene period that followed (10,000 BC and later).
but reality is that you are south asian muslim nothing else.
