NTPC is moving in sideways from the last several weeks. So, in such kind of movements, it's better to see weekly chart instead of daily chart. Below is NTPC technical chart on weekly time frame with ichimoku Kinko Hyo indicator.
On week ending 15-Oct-2010, NTPC price closed down below kumo at Rs.204.30. That was the first signal of its weakness and opportunity to book profit and start short-selling here.
Since then, its moving in downward direction. The resistance levels, as shown by kumo lines, are 176.40, 180.60 and 193.90. Closing above one resistance level can take price to next level.
Rs.160-163 is the immediate support level of NTPC.
For long term investor and for safe trading, take long position ONLY when it closes above 193.90 on weekly chart.