Create donut plot split into 3 sections.

triple_donut.py

import matplotlib.pyplot as plt
import numpy as np

fig, ax = plt.subplots()

size = 0.3
vals = [
    25,
    50,
    75
]

LABELS = [
    "coral health index",
    "reef health index",
    "other helath index"
]

normalized_vals = []
labels = []
for i in range(len(vals)):
    v = vals[i]*33/100
    normalized_vals.append(v)
    normalized_vals.append(33 - v)
    labels.append(str(vals[i]) + "%")
    labels.append(' ')

cmap = plt.get_cmap("tab20c")
inner_colors = cmap(np.array([1, 2, 5, 6, 9, 10]))

ax.pie(
    normalized_vals, radius=1-size, colors=inner_colors,
    wedgeprops=dict(width=size, edgecolor='w'),
    labels=labels
)

ax.set(aspect="equal", title='Health indicies')
plt.show()