Explanation:

The replacement level is the number of children needed to replace the parents, after accounting for fatalities, skewed sex ratio, infant mortality, etc. Population starts falling below this level.

• India has done very well with its family planning measures and now it is at replacement level fertility of 2.1, which is desirable.
• However, it needs to sustain population stabilisation because in some States like Sikkim, Andhra Pradesh, Delhi, Kerala and Karnataka, the total fertility rate is way below replacement level, which means it can experience in 30-40 years what China is experiencing now. 

Hence both statements are correct.