Mentors Comments:

• This is a direct question. Divide the question into two parts. Influence of Central Asian elements in Gandhara art and Greek elements in Gandhara art.
• Gandhara was an ancient state, a mahajanapada, in the Peshawar basin in the northwest portion of the ancient Indian subcontinent, present-day Afghanistan and Pakistan.
• Central Asian features:  Green phyllite and grey-blue mica schist, the basic shape has been cut out of stone, this is then plastered with lime plaster to give it a finished look,
• Greco- Bactrian features: Hellenistic features of Buddha, halo in the back, anthropomorphic traditions of Roman religion and represented the Buddha with a youthful Apollo-like face, dressed in garments resembling those seen on Roman imperial statues, great detailing such as curly hair, large forehead and ears, half-closed eyes.

Answer:

Gandhara school of art was one of the major schools of art in the history of ancient India. Although being an intricate part of Indian history, it is uniquely associated with the Greco-Roman style of art. The combination of these Greco-Roman and Indian ideas along with the influence of other foreign traditions such as from Central Asia, Iran and China resulted in the formation of a distinct style known as the Gandhara School of art.

Central Asian and Roman Influence:

• Artistic representation: Buddha is sometimes presented in Roman motifs like Triton
• Technique: Buddha of Gandhara sometimes through a wine scroll
• Anthropomorphism Tradition: Buddha in human form is inspired by Roman tradition.
• Dressing: The outer rope of Buddha of Gandhara like Kaya, Antarvasa resembles Roman gods.

Greco-Bactrian elements:

• Greek god as a protector in many images of Buddha in Gandhara; he is seen under the protection of Greek god Hercules.
• The drapery of Buddha statues similar to Parthian (modern Iran)drapery in Hellenistic cultures.
• Curly hair of Buddha statue also resembles similarity with Parthian style.
• Vajrapani found in the right hand of future Buddha is told as a transformed symbol of Hercules who is seen as a protector of Buddha.
• It is likely that Bactrian Greeks or Hellenized Bactrians played a part in the creation of the anthropomorphic image of Buddha.
• Gandhāran art in the forms derived from Iranian iconographies, such as ‘fire altars’ and the flame halo.
• Images of Buddha appear in the likeness of Apollo. The Saksha and Kurvera are posed in the fashion of the phidian Zeus and so on.
• The sculpture was one of the principal categories of Gandhāran art. It is represented by isolated statues and bas-reliefs decorating buildings, especially cult edifices. 
• The different parts of the body, especially muscles and moustaches were shown in a natural setting.
• Besides this, the clothes, hairstyle, decoration and ornamentation clearly indicate the influence of the Greek style.

Central Asia and Greco-Bactrian art made a considerable contribution to the development of Gandharan art. In its turn, it later affected the culture of the regions inhabited by Iranian people.