This paper reports the first experimental evidence of negative magneto-resistance (MR) induced by the chiral anomaly in a 3D Weyl semi-metal, TaAs. The authors observed clear Shubnikov de Haas (SdH) oscillations starting from very weak magnetic fields, which allowed them to determine the Berry phase accumulated along the cyclotron orbits to be π, confirming the presence of Weyl points. The negative MR was observed when the magnetic field was parallel to the current, with a maximum value of -30% at 9 T. This effect is attributed to the chiral anomaly, which causes the non-conservation of particle number with given chirality under the presence of parallel magnetic and electric fields. The study also revealed the coexistence of electron and hole carriers in TaAs, with an electron mobility of approximately 1.8 × 10^5 cm^2 V^-1 s^-1 at 10 K. The findings provide strong evidence for the existence of Weyl points in TaAs and open up new avenues for further research in this area.This paper reports the first experimental evidence of negative magneto-resistance (MR) induced by the chiral anomaly in a 3D Weyl semi-metal, TaAs. The authors observed clear Shubnikov de Haas (SdH) oscillations starting from very weak magnetic fields, which allowed them to determine the Berry phase accumulated along the cyclotron orbits to be π, confirming the presence of Weyl points. The negative MR was observed when the magnetic field was parallel to the current, with a maximum value of -30% at 9 T. This effect is attributed to the chiral anomaly, which causes the non-conservation of particle number with given chirality under the presence of parallel magnetic and electric fields. The study also revealed the coexistence of electron and hole carriers in TaAs, with an electron mobility of approximately 1.8 × 10^5 cm^2 V^-1 s^-1 at 10 K. The findings provide strong evidence for the existence of Weyl points in TaAs and open up new avenues for further research in this area.